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Code Issues Projects Releases Packages Wiki Activity Actions

Fix typos

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Marcello 2021-09-20 19:35:32 +02:00
parent 76550dfa3c
commit 5c0799df7f
118 changed files with 1150 additions and 1602 deletions
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49
Android/Activity.kt.md
View file

@ -50,7 +50,7 @@ class MainActivity : AppCompatActivity() {
### Passing data between activities
In *lauching* activity:
In *laughing* activity:
```kotlin
private fun openActivity() {
@ -58,7 +58,7 @@ private fun openActivity() {
//target to open Intent(opener, opened)
val intent = Intent(this, Activity::class.java)
//pass data to lauched activity
//pass data to launched activity
intent.putExtra("identifier", value)
startActivity(intent) //launch another activity
@ -76,7 +76,7 @@ val identifier = intent.get<Type>Extra("identifier")
### Resources Hooks
```kotlin
R.<resourceType>.<resourceName> //access to reource
R.<resourceType>.<resourceName> //access to resource
ContextCompat.getColor(this, colorResource) //extract color from resources
getString(stringResource) //extract string from resources
@ -98,14 +98,14 @@ in `Activity.kt`:
```kotlin
var element = findViewById(R.id.<id>) //old method
<id>.poperty = value //access and modify view contents
<id>.popery = value //access and modify view contents
```
## Activity Components
### Snackbar
Componed derived from material design. If using old API material design dependency must be set in gradle.
Component derived from material design. If using old API material design dependency must be set in gradle.
In `build.gradle (Module:app)`:
@ -144,10 +144,10 @@ startActivity(intent)
val intent = Intent(Intent.ACTION_SEND)
intent.setType("text/plain") //specifying shared content type
intent.putExtra(Intent.EXTRA_MAIL, "mail@address") //open mail client and precompile field if share w/ mail
intent.putExtra(Intent.EXTRA_MAIL, "mail@address") //open mail client and pre-compile field if share w/ mail
intent.putExtra(Intent.EXTRA_SUBJECT, "subject")
intent.putExtra(Intent.EXTRA_TEXT, "text") //necessary since type is text
startActivity(Initent.startChooser(intent, "chooser title")) //let user choose the share app
startActivity(Intent.startChooser(intent, "chooser title")) //let user choose the share app
```
### App Google Maps
@ -186,21 +186,22 @@ In `AndroidManifest.xml`:
//https://developer.android.com/training/permissions/requesting
//intercept OS response to permission popup
override fun onRequestPermissionResult(requestCode: Int, permissins: Array<out String>, grantResults: IntArray) {
override fun onRequestPermissionResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults)
}
fun checkCallPermission() {
//check if permission to make a call has been granted
if (ContextCompact.checkSelfPermission(context!!, android.Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {
// i permission has not been granted request it (opens OS popup, no listener aviable)
ActivityCompat.requestPermissions(context!!, arrrayOf(android.Manifest.permission.CALL_PHONE), requestCode) //request code neeeds to be specific for the permission
// if permission has not been granted request it (opens OS popup, no listener available)
// request code needs to be specific for the permission
ActivityCompat.requestPermissions(context!!, arrayOf(android.Manifest.permission.CALL_PHONE), requestCode)
} else {
call() //if permission has been already given
}
}
@SuppressLint("MissingPermission") // suppress warnig of unhandled permission (handled in checkCallPermission)
@SuppressLint("MissingPermission") // suppress warning of unhandled permission (handled in checkCallPermission)
fun call() {
val intent = Intent(Intent.ACTION_DIAL, Uri.parse("tel: <phone number>"))
startActivity(intent)
@ -230,11 +231,11 @@ recycleView.LayoutManager = layoutManager // assign LayoutManager for the recyc
// handle adapter var containing null value
if (array != null) {
adapter = RecyclerViewItemAdapter(array!!) // valorize adapter with a adaper object
recyclerView.adapter = adapter // assing adapter to the recyclerView
adapter = RecyclerViewItemAdapter(array!!) // valorize adapter with a adapter object
recyclerView.adapter = adapter // assign adapter to the recyclerView
}
// add or remom item
// add or remove item
// tell the adapter that something is changed
adapter?.notifyDataSetChanged()
@ -247,7 +248,7 @@ adapter?.notifyDataSetChanged()
```kotlin
webView.webViewClient = object : WebViewClient() {
// avoid openiing browsed by default, open webview instead
// avoid opening browsed by default, open webview instead
override fun shouldOverrideUrlLoading(view: WebView?, url: String?): Boolean {
view?.loadUrl(url) // handle every url
return true
@ -261,7 +262,7 @@ webView.webViewClient = object : WebViewClient() {
}
Intent(Intent.ACTION_VIEW, Uri.parse(url).apply){
startActivity(this) // open br br owser/app when the website changes to external URL
startActivity(this) // open browser/app when the website changes to external URL
}
return true
}
@ -291,7 +292,7 @@ Import in `build.gradle`:
implementation 'com.android.volley:volley:1.1.1'
```
Perrmissions in `AndroidManifest.xml`:
Permissions in `AndroidManifest.xml`:
```xml
<uses-permission android:name="android.permission.INTERNET" />
@ -299,7 +300,7 @@ Perrmissions in `AndroidManifest.xml`:
### Make the request
Subsequnt requests sould be delayed to avoid allowing the user to make too frequent requests.
Subsequent requests should be delayed to avoid allowing the user to make too frequent requests.
```kotlin
private lateinit var queue: RequestQueue
@ -358,14 +359,14 @@ private fun getJSONArrayRequest(){
override fun onStop() {
super.onStop()
queue?.cancellAll("TAG") // delete all request with a particular tag when the activity is closed (avoid crash)
queue?.cancelAll("TAG") // delete all request with a particular tag when the activity is closed (avoid crash)
}
```
### Parse JSON Request
```kotlin
Response.Litener { response ->
Response.Listener { response ->
var value = response.getSting("key")
}
```
@ -374,19 +375,19 @@ Response.Litener { response ->
### Singleton
Object instantiated during app init and is destroid only on app closing. It can be used for data persistance since is not affected by the destruction of an activity.
Object instantiated during app init and is destroyed only on app closing. It can be used for data persistance since is not affected by the destruction of an activity.
```kotlin
// Context: Interface to global information about an application environment.
class Singleton consturctor(context: Context) {
class Singleton constructor(context: Context) {
companion object {
@Volatile
private var INSTANCE: Singleton? = null
// syncronized makes sure that all instances of the singleton are actually the only existing one
fun getInstance(context: Contecxt) = INSTANCE ?: syncronized(this) {
// synchronized makes sure that all instances of the singleton are actually the only existing one
fun getInstance(context: Context) = INSTANCE ?: synchronized(this) {
INSTANCE ?: Singleton(context).also {
INSTANCE = it
}

4
Android/Adapter.kt.md
View file

@ -26,10 +26,10 @@ class RecipeAdapter : RecyclerView.Adapter<RecipeAdapter.ViewHolder> {
}
}
//adapter contructor, takes list of data
//adapter contractor, takes list of data
constructor(myDataset: ArrayList<Recipe>/*, mContext: Context?*/){
mDataset = myDataset
//mContenxt = mContext
//mContext = mContext
}

14
Android/Gradle & Building.md
View file

@ -18,18 +18,18 @@ android {
}
```
## Distribuiting the app
## Distributing the app
### APK vs Bundle
- APK: android executable, contains all assets of the app (multiplr versions for each device). The user downloads all the assets.
- Bundle: split the assets based on dedvice specs. The users donwloads only the assest needed for the target device.
- APK: android executable, contains all assets of the app (multiple versions for each device). The user downloads all the assets.
- Bundle: split the assets based on device specs. The users downloads only the assets needed for the target device.
### APK generation & [App Signing](https://developer.android.com/studio/publish/app-signing)
- **Key store path**: location where the keystore file will be stored.
- **Key store password**: secure password for the keystore (**to be rememberd**).
- **Key alias**: identifying name for the key (**to be rememberd**).
- **Key password**: secure password for the key (**to be rememberd**).
- **Key store password**: secure password for the keystore (**to be remembered**).
- **Key alias**: identifying name for the key (**to be remembered**).
- **Key password**: secure password for the key (**to be remembered**).
The ketstore identifies the app and it's developers. It's needed for APK generation and releases distribution.
The keystore identifies the app and it's developers. It's needed for APK generation and releases distribution.

6
Android/MapsActivity.md
View file

@ -2,13 +2,13 @@
[Google Maps Docs](https://developers.google.com/maps/documentation/android-sdk/intro)
Activity sould be **Google Maps Activity**.
Activity should be **Google Maps Activity**.
In `google_maps_api.xml`:
```xml
<resources>
<string name="google_maps_key" templateMergeStartegy="preserve", translateble="false">API_KEY</string>
<string name="google_maps_key" templateMergeStrategy="preserve", translatable="false">API_KEY</string>
</resources>
```
@ -63,7 +63,7 @@ class MapsActivity : AppCompatActivity(), OnMapReadyCallback,
mMap.setOnInfoWindowClickListener(this)
// Add a marker and move the camera
val location = LatLng(-34.0, 151.0) // set loaction with latitude and longitude
val location = LatLng(-34.0, 151.0) // set location with latitude and longitude
mMap.addMarker(MarkerOptions().position(location).title("Marker in ...")) // ad the marker to the map with a name and position
mMap.moveCamera(CameraUpdateFactory.newLatLng(location)) // move camera to the marker

12
Android/SQLite.md
View file

@ -31,17 +31,17 @@ class DatabaseHelper(
Make data persistent.
```kotlin
class AppSingleton consturctor(context: Context) {
class AppSingleton constructor(context: Context) {
var dataabse: SQLiteDatabase? = null // point to database file in memory
var database: SQLiteDatabase? = null // point to database file in memory
companion object {
@Volatile
private var INSTANCE: AppSingleton? = null
// syncronized makes sure that all instances of the singleton are actually the only existing one
fun getInstance(context: Contecxt) = INSTANCE ?: syncronized(this) {
// synchronized makes sure that all instances of the singleton are actually the only existing one
fun getInstance(context: Context) = INSTANCE ?: synchronized(this) {
INSTANCE ?: Singleton(context).also {
INSTANCE = it
}
@ -75,10 +75,10 @@ override fun onCreate() {
Controller to handle data from the objects and interact with the Database
```kotlin
sqLiteDatabse = AppISngleton.getInstance().database // reference to the database from the singleton
sqLiteDatabase = AppISingleton.getInstance().database // reference to the database from the singleton
contentValues = ContentValues() // dict like structure to insert data in DB
contentValuest.put("DB_Column", value) // put data in the structure
contentValues.put("DB_Column", value) // put data in the structure
// insertion query V1
sqLiteDatabase?.insert("table", null, contentValue)

8
Android/activity.xml.md
View file

@ -4,7 +4,7 @@
### Colors, Style, Strings
These resorsces are located in `app/src/main/res/values/<resource_type>.xml`
These resources are located in `app/src/main/res/values/<resource_type>.xml`
`@color/colorName` -> access to *color definition* in `colors.xml`
`@string/stringName` -> access to *string definition* in `strings.xml` (useful for localization)
`@style/styleName` -> access to *style definition* in `styles.xml`
@ -65,7 +65,7 @@ A **View Group** or **Layout** is a container of Views.
```
`android:layout_width`, `android:layout_heigth`:
`android:layout_width`, `android:layout_height`:
* fixed value (dp, sp)
* match_parent
@ -141,7 +141,7 @@ Layout that arranges other views either horizontally in a single column or verti
```xml
<!--ID is necessary for identification -->
<View
android:id="@+id/uniquieId"
android:id="@+id/uniqueId"
android:layout_width="value"
android:layout_height="value"
/>
@ -164,7 +164,7 @@ The scroll view can only have one child. If the child is a layout than the layou
```xml
<ScrollView
android:id="@+id/uniquieId"
android:id="@+id/uniqueId"
android:layout_width="value"
android:layout_height="value">
<!-- single child -->

38
Bash/Bash Commands.md
View file

@ -4,20 +4,20 @@
## Basic Commands
### Elevated Priviledges and Users
### Elevated Privileges and Users
[sudo vs su](https://unix.stackexchange.com/questions/35338/su-vs-sudo-s-vs-sudo-i-vs-sudo-bash/35342)
```bash
sudo su # login as root (user must be sudoer, root password not required) DANGEROUS
sudo -s # act as root and inherit current user enviroment (env as is now, along current dir and env vars) SAFE (can modify user enviroment)
sudo -i # act as root and and use a clean enviroment (goes to user's home, runs .bashrc) SAFEST
sudo su # login as root (user must be sudoers, root password not required) DANGEROUS
sudo -s # act as root and inherit current user environment (env as is now, along current dir and env vars) SAFE (can modify user environment)
sudo -i # act as root and and use a clean environment (goes to user's home, runs .bashrc) SAFEST
sudo COMMAND # run a command w\ root permissions
sudo -u USER COMMAND # run command as user
su # become root (must know root password) DANGEROUS
su - USER # change user and load it's home folder
su USER # change user but dont load it's home folder
su USER # change user but don't load it's home folder
```
### Getting Info
@ -51,7 +51,7 @@ popd # return to previous directory (before pushd)
```sh
touch FILE # change FILE timestamp fi exists, create file otherwise
cat [FILE] # concatenate files and print on statndard output (FD 1)
cat [FILE] # concatenate files and print on standard output (FD 1)
cat >> FILE # append following content ot file (Ctrl+D to stop)
file FILE # discover file extension and format
stat FILE # display file or file system status
@ -60,7 +60,7 @@ tail # output the last part of a file
tail [-nNUM] # output the last NUM lines
more # filter for paging through text one screenful at a time
less # opposite of more (display big file in pages), navigate with arrow keys or spacebar
less # opposite of more (display big file in pages), navigate with arrow keys or space bar
cut # remove sections from each line of files
cut -[d --delimiter=DELIM] # use DELIM instead of TAB for field delimiter
@ -74,10 +74,10 @@ rmdir DIRECTORY # remove directory only if is empty
mkdir DIRECTORY # make directories
mv SOURCE DESTINATION # move or raneme files
mv SOURCE DESTINATION # move or rename files
mv SOURCE DIRECTORY # move FILE to DIRECTORY
cp SOURCE DESTINATION # copy SOURCE to DESTIANTION
cp SOURCE DESTINATION # copy SOURCE to DESTINATION
```
### Files Permissions & Ownership
@ -125,7 +125,7 @@ chgrp [OPTION]... GROUP FILE... # change group ownership
find [path] [expression] # search file in directory hierarchy
find [start-position] -type f -name FILENAME # search for a file named "filename"
find [start-position] -type d -name DIRNAME # search for a directory named "dirname"
find [path] -exec <command> {} \; # ececute command on found items (identified by {})
find [path] -exec <command> {} \; # execute command on found items (identified by {})
[ -f "path" ] # test if a file exists
[ -d "path" ] # test if a folder exists
@ -140,11 +140,11 @@ command | sudo tee FILE # operate on file w/o using shell as su
echo # display a line of text
echo "string" > FILE # write lin of text to file
echo "string" >> FILE # append line o ftext to end of file (EOF)
echo "string" >> FILE # append line of text to end of file (EOF)
wget URL # download repositories to linux machine
curl # dovnlaod the contents of a URL
curl # download the contents of a URL
curl [-I --head] # Fetch the headers only
ps [-ax] # display processes
@ -161,8 +161,8 @@ diff FILES # compare files line by line
shellcheck FILE # shell linter
xargs [COMMAND] # build and execute command lines from standard input
# xargs reads items form the standard input, delimites by blanks or newlines, and executes the COMMAND one or more times with the items as argumests
watch [OPTIONS] COMMAND # execute a program periodically, showing output fullscreen
# xargs reads items form the standard input, delimited by blanks or newlines, and executes the COMMAND one or more times with the items as arguments
watch [OPTIONS] COMMAND # execute a program periodically, showing output full-screen
watch -n SECONDS COMMAND # execute command every SECONDS seconds (no less than 0.1 seconds)
```
@ -172,10 +172,10 @@ watch -n SECONDS COMMAND # execute command every SECONDS seconds (no less than
```bash
sed # stream editor for filtering and transforming text
sed -E "s/REGEX/replacement/" # subsitute text ONCE (-E uses modern REGEX)
sed -E "s/REGEX/replacement/g" # subsitute text multiple times (every match)
sed -E "s/REGEX/replacement/" # substitute text ONCE (-E uses modern REGEX)
sed -E "s/REGEX/replacement/g" # substitute text multiple times (every match)
wc [FILE] # print newline, word and byte countd for each file
wc [FILE] # print newline, word and byte count for each file
wc [-m --chars] FILE # print character count
wc [-c --bytes] FILE # print bytes count
wc [-l --lines] FILE # print lines count
@ -185,8 +185,8 @@ sort [FILE] # sort lines of a text file
uniq [INPUT [OUTPUT]] # report or omit repeated lines (from INPUT to OUTPUT)
uniq [-c --count] # prefix lines w/ number of occurrences
uniq [-d --repeated] # plrint only duplicare lines, one for each group
uniq [-D] # plrint only duplicare lines
uniq [-d --repeated] # print only duplicare lines, one for each group
uniq [-D] # print only duplicare lines
paste [FILE] # merge lines of files
paste [-d --delimiters=LIST] # use delimiters from LIST

32
Bash/Bash Scripting.md
View file

@ -10,7 +10,7 @@
Interactive mode --> shell waits for user's commands
Non-interactive mode --> shell runs scripts
## File & Directories Permissons
## File & Directories Permissions
File:
@ -35,12 +35,12 @@ Bash gets commands by reading lines.
As soon as it's read enough lines to compose a complete command, bash begins running that command.
Usually, commands are just a single line long. An interactive bash session reads lines from you at the prompt.
Non-interactive bash processes read their commands from a file or stream.
Files with a hashbang as their first line (and the executable permission) can be started by your system's kernel like any other program.
Files with a shebang as their first line (and the executable permission) can be started by your system's kernel like any other program.
### First Line Of Bash
`#!/bin/env bash`
Hashbang indicating whitch interpreter to use
shebang indicating which interpreter to use
### Simple Command
@ -73,7 +73,7 @@ command_1 || command_2 || ... # execute successive commands only if preceding o
{command_1; command_2; ...} # sequence of commands executed as one
```
### Functions (blocks of easely reusable code)
### Functions (blocks of easily reusable code)
`function_name () {compound_command}`
Bash does not accept func arguments, parentheses must be empty
@ -125,7 +125,7 @@ x>&-, x<&- # close FD x (stream disconnected from FD x)
`*` matches any kind of text (even no text).
`?` matches any single character.
`[characters]` mathces any single character in the given set.
`[characters]` matches any single character in the given set.
`[[:classname:]]` specify class of characters to match.
`{}` expand list of arguments (applies command to each one)
@ -137,7 +137,7 @@ x>&-, x<&- # close FD x (stream disconnected from FD x)
`@(pattern [| pattern ...])` matches when any of the patterns in the list appears just once. ("one of ...").
`!(pattern [| pattern ...])` matches only when none of the patterns in the list appear. ("none of ...").
## Command Substituition
## Command Substitution
With Command Substitution, we effectively write a command within a command, and we ask bash to expand the inner command into its output and use that output as argument data for the main command.
@ -148,9 +148,9 @@ $(inner_command) # $ --> value-expansion prefix
## Shell Variables
```bash
varname=value # variable assignement
varname="$(command)" # command sobstituition, MUST be double-quoted
"$varname", "${varname}" # variable expansion, MUST be double-quoted (name substituited w/ varaible content)
varname=value # variable assignment
varname="$(command)" # command substitution, MUST be double-quoted
"$varname", "${varname}" # variable expansion, MUST be double-quoted (name substituted w/ variable content)
$$ # pid
$# # number of arguments passed
@ -158,7 +158,7 @@ $@ # all arguments passed
${n} # n-th argument passed to the command
$0 # name of the script
$_ # last argument passed to the command
$? # error message of the last (previous) comman
$? # error message of the last (previous) command
!! # executes last command used (echo !! prints the last command)
```
@ -173,7 +173,7 @@ $? # error message of the last (previous) comman
`${parameter/#pattern/replacement}` replaces the string that matches the pattern at the beginning of the value with the replacement.
`${parameter/%pattern/replacement}` replaces the string that matches the pattern at the end of the value with the replacement.
`${#parameter}` expands the length of the value (in bytes).
`${parametr:start[:length]}` expands a part of the value, starting at start, length bytes long.
`${parameter:start[:length]}` expands a part of the value, starting at start, length bytes long.
Counts from the end rather than the beginning by using a (space followed by a) negative value.
`${parameter[^|^^|,|,,][pattern]}` expands the transformed value, either upper-casing or lower-casing the first or all characters that match the pattern.
Omit the pattern to match any character.
@ -195,7 +195,7 @@ fi
### Test Command
`[[ arggument_1 <operator> argument_2 ]]`
`[[ argument_1 <operator> argument_2 ]]`
### Arithmetic expansion and evaluation
@ -212,7 +212,7 @@ fi
[[ "$a" -le "$b" ]] # less than or equal to
```
### Arithmetic Comperison Operators
### Arithmetic Comparison Operators
```bash
(("$a" > "$b")) # greater than
@ -221,10 +221,10 @@ fi
(("$a" <= "$b")) # less than or equal to
```
### String Compatison Operators
### String Comparison Operators
```bash
[ "$a" = "$b" ] # is equal to (whitespace atoun operator)
[ "$a" = "$b" ] # is equal to (whitespace around operator)
[[ $a == z* ]] # True if $a starts with an "z" (pattern matching)
[[ $a == "z*" ]] # True if $a is equal to z* (literal matching)
@ -244,7 +244,7 @@ fi
```bash
command_1 || command_2 # if command_1 fails executes command_2
command_1 && command_2 # executes command_2 only if command_1 succedes
command_1 && command_2 # executes command_2 only if command_1 succeeds
```
## Loops

96
C++/C++.md
View file

@ -34,12 +34,12 @@ const type constant_name = value;
```cpp
#include <cstdlib>
system("pause");
getchar(); // waits imput from keyboard, if is last instruction will prevent closing console until satisfied
getchar(); // waits input from keyboard, if is last instruction will prevent closing console until satisfied
```
### Namespace definition
Can be omitted and replaced by namespce`::`
Can be omitted and replaced by namespace`::`
`using namespace <namespace>;`
### Main Function
@ -72,7 +72,7 @@ Type | Value Range | Byte
`short` | -32768 to 32765 | 1
`unsigned short` | 0 to 65535 | 1
`int` | -2147483648 to 2147483647 | 4
`unisgned int` | 0 to 4294967295 | 4
`unsigned int` | 0 to 4294967295 | 4
`long` | -2147483648 to 2147483647 | 4
`unsigned long` | 0 to 4294967295 | 4
`long long` | | 8
@ -105,7 +105,7 @@ Example | Type
Example | Type
------------|-------------
`3.14159L` | long double
`60.22e23f` | flaot
`60.22e23f` | float
Code | Value
----------|---------------
@ -123,7 +123,7 @@ Code | Value
Escape Character | Character
-------------------|-----------------------------
`\n` | neweline
`\n` | newline
`\r` | carriage return
`\t` | tab
`\v` | vertical tab
@ -140,7 +140,7 @@ Escape Character | Character
```cpp
cout << expression; // print line on screen (no automatic newline)
cout << expressin_1 << expreeeion_2; // concatenation of outputs
cout << expression_1 << expression_2; // concatenation of outputs
cout << expression << "\n"; // print line on screen
cout << expression << endl; // print line on screen
@ -153,19 +153,19 @@ printf_s("text %<fmt_spec>", variable);
### Input
```cpp
#iclude <iostream>
#include <iostream>
cin >> var; //space terminates value
cin >> var_1 >> var_2;
//if used after cin >> MUST clear buffer with cin.ignore(), cin.sync() or std::ws
getline(stream, string, delimiter) //read input from stream (usially CIN) and store in in string, a different delimiter character can be set.
getline(stream, string, delimiter) //read input from stream (usually CIN) and store in in string, a different delimiter character can be set.
#include <stdio.h>
scanf("%<fmt_spec>", &variable); // has problems, use SCANF_S
scanf_s("%<fmt_spec>", &variable); //return number of succescully accepted inputs
scanf_s("%<fmt_spec>", &variable); //return number of successfully accepted inputs
```
### Fromat Specifiers %[width].[lenght][specifier]
### Format Specifiers %[width].[length][specifier]
Specifier | Specified Format
------------|-----------------------------------------
@ -210,9 +210,9 @@ if (!(cin >> var)) // if cin fails to get an input
#include <iomanip>
cout << stew(print_size) << setprecision(num_digits) << var; //usage
setbase(base) //set numberica base [dec, hex, oct]
setbase(base) //set numeric base [dec, hex, oct]
setw(print_size) //set the total number of characters to display
setprecision(num_digits) //sets the number of decimal digits to siaplay
setprecision(num_digits) //sets the number of decimal digits to display
setfill(character) //use character to fill space between words
```
@ -263,7 +263,7 @@ a `^` b, a `xor` b, | bitwise **XOR**
a `<<` b | bitwise left shift
a `>>` b | bitwise right shift
### Compound Assignement O
### Compound Assignment O
Operator | Operation
------------|------------
@ -297,7 +297,7 @@ abs(x); // absolute value
labs(x); //absolute value if x is long, result is long
fabs(x); //absolute value if x i float, result is float
sqrt(x); // square root
ceil(x); // ceil function (next initeger)
ceil(x); // ceil function (next integer)
floor(x); // floor function (integer part of x)
log(x); // natural log of x
log10(x); // log base 10 of x
@ -337,7 +337,7 @@ isxdigit(c); //true if c is HEX DIGIT
```cpp
#include <ctype.n>
tolower(c); //transfromas charatcer in lowercase
tolower(c); //transforms character in lowercase
toupper(c); //transform character in uppercase
```
@ -346,7 +346,7 @@ toupper(c); //transform character in uppercase
```cpp
#include <time>
#include <stdlib.h>
srand(time(NULL)); //initzialize seed
srand(time(NULL)); //initialize seed
var = rand() //random number
var = (rand() % max + 1) //random numbers between 0 & max
var = (rand() % (max - min + 1)) + min //random numbers between min & max
@ -367,7 +367,7 @@ fflush(FILE); // empty output buffer end write its content on argument passed
#include <string>
string string_name = "string_content"; //string declaration
string string_name = string("strintg_content"); // string creation w/ constructor
string string_name = string("string_content"); // string creation w/ constructor
string.length //returns the length of the string
@ -383,9 +383,9 @@ string[pos] //returns char at index pos
### String Functions
```cpp
string.c_str() //transfroms the string in pointer to char[] (char array aka C string) ter,iomated by '\0'
string.c_str() //transforms the string in pointer to char[] (char array aka C string) terminated by '\0'
strlen(string); //return lenght (num of chars) of the string
strlen(string); //return length (num of chars) of the string
strcat(destination, source); //appends chars of string2 to string1
strncat(string1, string2, nchar); //appends the first n chars of string 2 to string1
strcpy(string1, string2.c_str()); //copies string2 into string1 char by char
@ -394,7 +394,7 @@ strcmp(string1, string2); //compares string1 w/ string2
strncmp(string1, string2, n); //compares first n chars
//returns < 0 if string1 precedes string2
//returns 0 if string1 == string2
// returns > 0 if string1 succedes string2
// returns > 0 if string1 succeeds string2
strchr(string, c); //returns index of c in string if it exists, NULL otherwise
strstr(string1, string2); //returns pointer to starting index of string1 in string2
strpbrk(string, charSet); //Returns a pointer to the first occurrence of any character from strCharSet in str, or a NULL pointer if the two string arguments have no characters in common.
@ -430,7 +430,7 @@ vector<type> vector_name = {values}; //variable length array
```cpp
if (condition)
//single istruction
//single instruction
if (condition) {
@ -448,7 +448,7 @@ if (condition) {
}
```
## IF-ELSE mutli-branch
## IF-ELSE multi-branch
```cpp
if (condition) {
@ -532,7 +532,7 @@ To return multiple variables those variables can be passed by reference so that
### Standard Function
```cpp
type functionName (parameters) { //parametri formali aka arguents
type functionName (parameters) { //parametri formali aka arguments
//code here
return <expression>;
}
@ -548,7 +548,7 @@ void functionName (parameters) {
### Arguments passed by reference without pointers
Passing arguments by reference causes modifications made inside the funtion to be propagated to the values outside.
Passing arguments by reference causes modifications made inside the function to be propagated to the values outside.
Passing arguments by values copies the values to the arguments: changes remain inside the function.
```cpp
@ -562,7 +562,7 @@ type functionName (type &argument1, ...) {
### Arguments passed by reference with pointers
Passing arguments by reference causes modifications made inside the funtion to be propagated to the values outside.
Passing arguments by reference causes modifications made inside the function to be propagated to the values outside.
Passing arguments by values copies the values to the arguments: changes remain inside the function.
```cpp
@ -578,22 +578,22 @@ type function_name (type *argument_1, ...) {
```cpp
type arrayName[dimension]; //array declaration
type arrayName[dimension] = {value1, value2, ...}; //array declaration & inizialization, values number must match dimension
type arrayName[dimension] = {value1, value2, ...}; //array declaration & initialization, values number must match dimension
array[index] //item access, index starts at 0 (zero)
array[index] = value; //value assignement at position index
array[index] = value; //value assignment at position index
```
## String as array of Chars
```cpp
char string[] = "text"; //converts string in char array, string length determines dimesion of the array
char string[] = "text"; //converts string in char array, string length determines dimension of the array
string str = string[] //a array of chars is automatically converted to a string
```
## Array as function parameter
The dimesion is not specified because it is determined by the passed array.
The dimension is not specified because it is determined by the passed array.
The array is passed by reference.
```cpp
@ -601,7 +601,7 @@ type function(type array[]){
//code here
}
//array is not modificable inside the function (READ ONLY)
//array is not modifiable inside the function (READ ONLY)
type function(const type array[]){
//code here
}
@ -624,8 +624,8 @@ type function(type matrix[][columns]){
//code here
};
//martix values READ ONLY
type function(const type matric[][columns]){
//matrix values READ ONLY
type function(const type matrix[][columns]){
//code here
}
@ -636,7 +636,7 @@ type function(type matrix[][dim2]...[dimN]){
## Record (struct)
List of non omogeneous items
List of non homogeneous items
### Struct Definition (before functions, outside main)
@ -654,10 +654,10 @@ variable.field //field access
## Pointers
Pointers hold memory adresses of declared variables, they should be initialized to NULL.
Pointers hold memory addresses of declared variables, they should be initialized to NULL.
```cpp
type *pointer = &variable; //pointer init and assignement
type *pointer = &variable; //pointer init and assignment
type *pointer = NULL;
type *pointer = otherPointer;
type **pointerToPointer = &pointer; // pointerToPointer -> pointer -> variable
@ -668,7 +668,7 @@ pointer type and variable type **must** match.
(*) --> "value pointed to by"
```cpp
pointer //addres of pointed value (value of variable)
pointer //address of pointed value (value of variable)
*pointer //value of pointed variable
**pointer //value pointed by *pointer (pointer to pointer)
```
@ -690,15 +690,15 @@ pointer++; //change pointed value to successive "cell" of array
func(array) //pass entire array to function (no need to use (&) to extract address)
type func(type* array){
array[index] //acces to item of array at index
array[index] //access to item of array at index
}
```
### Pointer to Struct
```cpp
(*structPointer).field //acces to field value
structPointer->structField //acces to field value
(*structPointer).field //access to field value
structPointer->structField //access to field value
```
## Dynamic Structures
@ -711,7 +711,7 @@ Every node is composed by two parts:
* the value (item)
* pointer to successive node
**Lists** are *linear* dinamyc structures in which is only defined the preceding and succeding item. A List is a group of homogeneous items (all of the same type).
**Lists** are *linear* dynamic structures in which is only defined the preceding and succeeding item. A List is a group of homogeneous items (all of the same type).
**Trees**, **Graphs** are non *linear* dynamic structures in which an item cha have multiple successors.
@ -728,7 +728,7 @@ struct Node {
}
```
#### Node Instertion
#### Node Insertion
```cpp
Node *stackNode; //current node
@ -740,7 +740,7 @@ int nodeValue;
stackNode = new Node; //create new node
stackNode->value = nodevalue; //valorize node
stackNode->next = head; //update node poiter to old head adding it to the stack
stackNode->next = head; //update node pointer to old head adding it to the stack
head = stackNode; //update head to point to new first node
```
@ -783,12 +783,12 @@ Thus the first and last node will have a component empty since they only point t
### Dynamic Memory Allocation
C/C++ does not automatically free allocated memory when nodes are deleted. It must be done manuallty.
C/C++ does not automatically free allocated memory when nodes are deleted. It must be done manually.
In **C++**:
* `new` is used to allocate memory dynamically.
* `delete` is use to free the dinamically allocated memory.
* `delete` is use to free the dynamically allocated memory.
In **C**:
@ -807,7 +807,7 @@ free(pointer) //freeing of memory
The object oriented approach is based on the use of *streams*.
A **Stream** can be considered a stream of data that passes sequentially from a source to a destination.
The avaiable classes in C++ to operate on files are:
The available classes in C++ to operate on files are:
* `ifstream` for the input (reading)
* `ofstream` for the output (writing)
@ -822,7 +822,7 @@ ifstream file;
file.open("filename"); //read from file
ofstream file;
file.open("filename"); //writo to file
file.open("filename"); //write to file
fstream file;
@ -836,7 +836,7 @@ file.open("filename", ios::binary); //opens file in binary format
```
If file opening fails the stream has value 0, otherwise the value is the assigned memory address.
Opening modes can be conbined with the OR operator: `ios::mode | ios::mode`.
Opening modes can be combined with the OR operator: `ios::mode | ios::mode`.
### File Reading & Writing
@ -858,5 +858,5 @@ do {
Once a stream is in a **state of error** it will remain so until the status flags are *explicitly resetted*. The input operations on such a stream are *void* until the reset happens.
To clear the status of a stream the `clear()` method is used.
Furthermore, when an error on the stream happens **the stream is not cleared** of it's charaters contents.
Furthermore, when an error on the stream happens **the stream is not cleared** of it's characters contents.
To clear the stream contents the `ignore()` method is used.

46
Database/MongoDB.md
View file

@ -2,7 +2,7 @@
The database is a container of **collections**. The collections are containers of **documents**.
The documents are _schema-less_ that is they have a dynamic structure that can change between documents in the same colletion.
The documents are _schema-less_ that is they have a dynamic structure that can change between documents in the same collection.
## Data Types
@ -17,7 +17,7 @@ The documents are _schema-less_ that is they have a dynamic structure that can c
| Embedded Document | `{"a": {...}}` |
| Embedded Array | `{"b": [...]}` |
It's mandatory for each document ot have an uniwue field `_id`.
It's mandatory for each document ot have an unique field `_id`.
MongoDB automatically creates an `ObjectId()` if it's not provided.
## Databases & Collections Usage
@ -69,7 +69,7 @@ db.<collection>.insertOne({document}) # implicit collection creation
`$<key>` is used to access the value of the field dynamically
```json
{ "$expr": { <expression> } } // aggregetion expresion, variables, conditional expressions
{ "$expr": { <expression> } } // aggregation expression, variables, conditional expressions
{ "$expr": { "$comparison_operator": [ "$<key>", "$<key>" ] } } // compare field values
```
@ -80,13 +80,13 @@ db.<collection>.insertOne({document}) # implicit collection creation
It's possible to insert a single document with the command `insertOne()` or multiple documents with `insertMany()`.
Isertion results:
Insertion results:
- error -> rollback
- success -> entire documents gets saved
```sh
# explicit collection creation, all options are otional
# explicit collection creation, all options are optional
db.createCollection( <name>,
{
capped: <boolean>,
@ -121,7 +121,7 @@ db.<collection>.insertMany([ { document }, { document } ] , { "ordered": false }
```sh
db.<collection>.findOne() # find only one document
db.<collection>.find(filter) # show selected documents
db.<collection>.find(filter, {"<key>": 1}) # show selected values form documents (1 or true => show, 0 or false => dont show, cant mix 0 and 1)
db.<collection>.find(filter, {"<key>": 1}) # show selected values form documents (1 or true => show, 0 or false => don't show, cant mix 0 and 1)
db.<collection>.find(filter, {_id: 0, "<key>": 1}) # only _id can be set to 0 with other keys at 1
db.<collection>.find().pretty() # show documents formatted
db.<collection>.find().limit(n) # show n documents
@ -155,7 +155,7 @@ db.<collection>.find().hint( { $natural : -1 } ) # force the query to perform a
```sh
db.<collection>.updateOne(filter, $set: {"<key>": value}) # add or modify values
db.<collection>.updateOne(filter, $set: {"<key>": value}, {upsert: true}) # add or modify values, if attribute doesent exists create it
db.<collection>.updateOne(filter, $set: {"<key>": value}, {upsert: true}) # add or modify values, if attribute doesn't exists create it
db.<collection>.updateMany(filter, update)
@ -175,7 +175,7 @@ db.dropDatabase() # delete entire database
## [Mongoimport](https://docs.mongodb.com/database-tools/mongoimport/)
Utility to import all docs into a specified collection.
If the collection alredy exists `--drop` deletes it before reuploading it.
If the collection already exists `--drop` deletes it before reuploading it.
**WARNING**: CSV separators must be commas (`,`)
```sh
@ -228,17 +228,17 @@ mongoexport --collection=<collection> <options> <connection-string>
**Nested / Embedded Documents**:
- Group data locically
- Group data logically
- Optimal for data belonging together that do not overlap
- Should avoid nesting too deep or making too long arrays (max doc size 16 mb)
```json
{
_id: Objectid()
"_id": Objectid()
"<key>": "value"
"<key>": "value"
innerDocument: {
"innerDocument": {
"<key>": "value"
"<key>": "value"
}
@ -249,19 +249,19 @@ mongoexport --collection=<collection> <options> <connection-string>
- Divide data between collections
- Optimal for related but shared data used in relations or stand-alone
- Allows to overtake nidification and size limits
- Allows to overtake nesting and size limits
NoSQL databases do not have relations and references. It's the app that has to handle them.
```json
{
"<key>": "value"
references: ["id1", "id2"]
"references": ["id1", "id2"]
}
// referenced
{
_id: "id1"
"_id": "id1"
"<key>": "value"
}
```
@ -273,7 +273,7 @@ Indexes support the efficient execution of queries in MongoDB.
Without indexes, MongoDB must perform a _collection scan_ (_COLLSCAN_): scan every document in a collection, to select those documents that match the query statement.
If an appropriate index exists for a query, MongoDB can use the index to limit the number of documents it must inspect (_IXSCAN_).
Indexes are special data structures that store a small portion of the collection’s data set in an easy to traverse form. The index stores the value of a specific field or set of fields, ordered by the value of the field. The ordering of the index entries supports efficient equality matches and range-based query operations. In addition, MongoDB can return sorted results by using the ordering in the index.
Indexes are special data structures that store a small portion of the collection's data set in an easy to traverse form. The index stores the value of a specific field or set of fields, ordered by the value of the field. The ordering of the index entries supports efficient equality matches and range-based query operations. In addition, MongoDB can return sorted results by using the ordering in the index.
Indexes _slow down writing operations_ since the index must be updated at every writing.
@ -283,13 +283,13 @@ Indexes _slow down writing operations_ since the index must be updated at every
- **Normal**: Fields sorted by name
- **Compound**: Multiple Fields sorted by name
- **Multykey**: values of sorted arrays
- **Multikey**: values of sorted arrays
- **Text**: Ordered text fragments
- **Geospatial**: ordered geodata
**Sparse** indexes only contain entries for documents that have the indexed field, even if the index field contains a null value. The index skips over any document that is missing the indexed field.
### Diagnosys and query planning
### Diagnosis and query planning
```sh
db.<collection>.find({...}).explain() # explain won't accept other functions
@ -345,9 +345,9 @@ Profiling Levels:
Logs are saved in the `system.profile` _capped_ collection.
```sh
db.setProgilingLevel(n) # set profiler level
db.setProfilingLevel(n) # set profiler level
db.setProfilingLevel(1, { slowms: <ms> })
db.getProfilingStatus() # check profiler satus
db.getProfilingStatus() # check profiler status
db.system.profile.find().limit(n).sort( {} ).pretty() # see logs
db.system.profile.find().limit(n).sort( { ts : -1 } ).pretty() # sort by decreasing timestamp
@ -358,7 +358,7 @@ db.system.profile.find().limit(n).sort( { ts : -1 } ).pretty() # sort by decrea
**Authentication**: identifies valid users
**Authorization**: identifies what a user can do
- **userAdminAnyDatabase**: can admin every db in the istance (role must be created on admin db)
- **userAdminAnyDatabase**: can admin every db in the instance (role must be created on admin db)
- **userAdmin**: can admin the specific db in which is created
- **readWrite**: can read and write in the specific db in which is created
- **read**: can read the specific db in which is created
@ -391,7 +391,7 @@ db.createUser(
## Sharding
**Sharding** is a MongoDB concept through which big datasests are subdivided in smaller sets and distribuited towards multiple instances of MongoDB.
**Sharding** is a MongoDB concept through which big datasets are subdivided in smaller sets and distributed towards multiple instances of MongoDB.
It's a technique used to improve the performances of large queries towards large quantities of data that require al lot of resources from the server.
A collection containing several documents is splitted in more smaller collections (_shards_)
@ -400,7 +400,7 @@ Shards are implemented via cluster that are none other a group of MongoDB instan
Shard components are:
- Shards (min 2), instances of MongoDB that contain a subset of the data
- A config server, instasnce of MongoDB which contains metadata on the cluster, that is the set of instances that have the shard data.
- A config server, instance of MongoDB which contains metadata on the cluster, that is the set of instances that have the shard data.
- A router (or `mongos`), instance of MongoDB used to redirect the user instructions from the client to the correct server.
![Shared Cluster](../.images/mongodb_shared-cluster.png "Components of a shared cluster")
@ -413,7 +413,7 @@ A **replica set** in MongoDB is a group of `mongod` processes that maintain the
Sequence of operations applied to a collection as a _pipeline_ to get a result: `db.collection.aggregate(pipeline, options)`.
[Aggragations Stages][aggeregation_stages_docs]:
[Aggregations Stages][aggeregation_stages_docs]:
- `$lookup`: Right Join
- `$match`: Where

6
Database/Redis.md
View file

@ -45,7 +45,7 @@ RPUSH <key> <value1> <value2> ... # add one or more values to the end of the lis
LPUSH <key> <value1> <value2> ... # add one or more values to the start of a list
LLEN # number of items in the list
LRANGE <key> <start_index> <end_index> # return a subset of the list, end index included. Negative indexes caout backwards from the end
LRANGE <key> <start_index> <end_index> # return a subset of the list, end index included. Negative indexes count backwards from the end
LPOP # remove and return the first item fro the list
RPOP # remove and return the last item fro the list
@ -56,7 +56,7 @@ RPOP # remove and return the last item fro the list
A set is similar to a list, except it does not have a specific order and each element may only appear once.
```sh
SADD <key> <value1> <value2> ... # add one or more values to the set (retunr 0 if values are alredy inside)
SADD <key> <value1> <value2> ... # add one or more values to the set (return 0 if values are already inside)
SREM <key> <value> # remove the given member from the set, return 1 or 0 to signal if the member was actually there or not.
SPOP <key> <value> # remove and return value from the set
@ -97,7 +97,7 @@ HGET <key> <field> # get data on a single field
HKEYS <key> # get all the fields in a hash
HVALS <key> # get all the values in a hash
HDEL <key> <field_1> <field_2> ... # delete one or more field hases
HDEL <key> <field_1> <field_2> ... # delete one or more field hashes
HMGET <key> <field> [<field> ...] # get the values of all the given hash fields
HMSET <key> <field> <value> [<field> <value> ...] # set multiple hash fields to multiple values

61
Database/SQL.md
View file

@ -6,7 +6,7 @@
```sql
show databases; -- mostra database
CREATE DATABASE <database>; -- dataabse creation
CREATE DATABASE <database>; -- database creation
use <database_name>; -- usa un database particolare
exit; -- exit mysql
@ -67,7 +67,7 @@ ALTER TABLE <table>
```sql
INSERT INTO <table> (field_1, ...) VALUES (value_1, ...), (value_1, ...);
INSERT INTO <table> VALUES (value_1, ...), (value_1, ...); -- field order MUST respest tables's columns order
INSERT INTO <table> VALUES (value_1, ...), (value_1, ...); -- field order MUST respect tables's columns order
```
### Data Update
@ -93,36 +93,36 @@ SHOW columns FROM <table>; -- show table columns
DESCRIBE <table>; -- shows table
```
### Alias Tabelle
### Alias
```sql
SELECT <field/funzione> as <alias>; -- mostra <field/funzione> con nome <alias>
SELECT <field> as <alias>; -- shows <field/funzione> with name <alias>
```
### Selezione Condizionale
### Conditional Selection
```sql
SELECT * FROM <table> WHERE <condition>; -- mostra elementi che rispettano la condizione
AND, OR, NOT -- connettivi logici
SELECT * FROM <table> WHERE <condition>; -- shows elements that satisfy the condition
AND, OR, NOT -- logic connectors
SELECT * FROM <table> WHERE <field> Between <value_1> AND <value_2>;
```
### Ordinamento
### Ordering
```sql
SELECT * FROM <table> ORDER BY <field>, ...; -- mostra tabella ordinata in base a colonna <field>
SELECT * FROM <table> ORDER BY <field>, ... DESC; -- mostra tabella ordinata decrescente in base a colonna <field>
SELECT * FROM <table> ORDER BY <field>, ... LIMIT n; -- mostra tabella ordinata in base a colonna <field>, mostra n elementi
SELECT * FROM <table> ORDER BY <field>, ...; -- shows the table ordered by <field>
SELECT * FROM <table> ORDER BY <field>, ... DESC; -- shows the table ordered by <field>, decreasing order
SELECT * FROM <table> ORDER BY <field>, ... LIMIT n; -- shows the table ordered by <field>, shows n items
SELECT TOP(n) * FROM <table> ORDER BY <field>, ...; -- T-SQL
```
## Raggruppamento
## Grouping
```sql
SELECT * FROM <table> GROUP BY <field>;
SELECT * FROM <table> GROUP BY <field> HAVING <condition>;
SELECT DISTINCT <field> FROM <table>; -- mostra elementi senza riperizioni
SELECT DISTINCT <field> FROM <table>; -- shows elements without repetitions
```
### Ricerca caratteri in valori
@ -130,10 +130,10 @@ SELECT DISTINCT <field> FROM <table>; -- mostra elementi senza riperizioni
`%` 0+ caratteri
```sql
SELECT * FROM <table> WHERE <field> LIKE '<char>%'; -- seleziona elemnti in <field> inizianti per <char>
SELECT * FROM <table> WHERE <field> LIKE '%<char>'; -- seleziona elemnti in <field> terminanti per <char>
SELECT * FROM <table> WHERE <field> LIKE '%<char>%'; -- seleziona elemnti in <field> contenenti <char>
SELECT * FROM <table> WHERE <field> NOT LIKE '%<char>%'; -- seleziona elemnti in <field> non contenenti <char>
SELECT * FROM <table> WHERE <field> LIKE '<char>%'; -- selects items in <field> that start with <char>
SELECT * FROM <table> WHERE <field> LIKE '%<char>'; -- selects items in <field> that end with <char>
SELECT * FROM <table> WHERE <field> LIKE '%<char>%'; -- selects items in <field> that contain <char>
SELECT * FROM <table> WHERE <field> NOT LIKE '%<char>%'; -- selects items in <field> that do not contain <char>
```
### Selection from multiple tables
@ -143,18 +143,18 @@ SELECT a.<field>, b.<field> FROM <table> AS a, <table> AS b
WHERE a.<field> ...;
```
## Funzioni
## Functions
```sql
SELECT COUNT(*) FROM <field>; -- conta numero elemneti nel campo
SELECT MIN(*) FROM <table>; -- restituisce il valore minimo
SELECT MAX(*) FROM <table>; -- restituisce valore massimo
SELECT AVG(*) FROM <table>; -- media valori del campo
SELECT COUNT(*) FROM <field>; -- count of items in <field>
SELECT MIN(*) FROM <table>; -- min value
SELECT MAX(*) FROM <table>; -- max value
SELECT AVG(*) FROM <table>; -- mean of values
ALL (SELECT ...)
ANY (SELECT ...)
```
## Query Annidate
## Nested Queries
```sql
SELECT * FROM <table> WHERE EXISTS (SELECT * FROM <table>) -- selected field existing in subquery
@ -181,13 +181,10 @@ INSERT INTO <table>
## Join
Permette di legare due tabelle correlando i dati, le tabelle devono avere almeno un campo in comune.
Primary key deve comparire in altra tabella come foreign key.
```sql
SELECT * FROM <table1> JOIN <table2> ON <table1>.<field> = <table2>.<field>; -- seleziono tutti gli elementi che hanno una relarione tra le due tabelle
SELECT * FROM <table1> LEFT JOIN <table2> ON <condition>; -- seleziona tutti gli elementi di table1 e i eventuali elementi richiamati dal join
SELECT * FROM <table1> RIGHT JOIN <tabl2> ON <condition> -- -- seleziona tutti gli elementi di table2 e i eventuali elementi richiamati dal join
SELECT * FROM <table1> JOIN <table2> ON <table1>.<field> = <table2>.<field>;
SELECT * FROM <table1> LEFT JOIN <table2> ON <condition>;
SELECT * FROM <table1> RIGHT JOIN <table2> ON <condition>
```
[Inner Join, Left Join, Right Join, Full Outer Join](https://www.diffen.com/difference/Inner_Join_vs_Outer_Join)
@ -202,7 +199,7 @@ JOIN <table3> ON <table2>.<field> = <table3>.<field>;
[char, nchar, varchar, nvarchar](https://stackoverflow.com/questions/176514/what-is-the-difference-between-char-nchar-varchar-and-nvarchar-in-sql-server)
***
---
## T-SQL (MSSQL Server)
@ -230,7 +227,7 @@ DECLARE @var_name <type>
SET @var_name = <value>
-- use in query (memorize data)
SELECT @var_name = COUNT(*) -- query won't show results in the "table view" sice param is used in SELECT
SELECT @var_name = COUNT(*) -- query won't show results in the "table view" since param is used in SELECT
FROM <table> ...
-- display message (query won't show results in the "table view")
@ -263,7 +260,7 @@ CREATE PROCEDURE <Procedure_Name>
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from interfering with SELECT statements.
SET NOCOUNT ON; -- dont return number of selected rows
SET NOCOUNT ON; -- don't return number of selected rows
-- Insert statements for procedure here
SELECT ...

4
DotNet/ASP.NET/App Configuration.md
View file

@ -73,7 +73,7 @@ namespace App
// or
services.AddControllers(); // controllers w/o views
//or
sevices.AddControllersWithViews(); // MVC Controllers
services.AddControllersWithViews(); // MVC Controllers
//or
services.AddServerSideBlazor(); // needs Razor Pages
@ -147,7 +147,7 @@ Connection Strings & Secrets.
## `launchsettings.json`
Launch Settings & Deployement Settings.
Launch Settings & Deployment Settings.
```json
{

6
DotNet/ASP.NET/Blazor.md
View file

@ -16,7 +16,7 @@ The component class is usually written in the form of a Razor markup page with a
## Project Structure & Important Files
### Blazor Server Project Stucture
### Blazor Server Project Structure
```txt
Project
@ -45,7 +45,7 @@ Project
|- App.razor --> component root of the app
|
|- appsettings.json --> application settings
|- Program.cs --> App entrypoint
|- Program.cs --> App entry-point
|- Startup.cs --> services and middleware configs
```
@ -78,7 +78,7 @@ Project
|- App.razor --> component root of the app
|
|- appsettings.json --> application settings
|- Program.cs --> App entrypoint
|- Program.cs --> App entry-point
```
### Blazor PWA Project Structure

34
DotNet/ASP.NET/Filters.md
View file

@ -1,6 +1,6 @@
# [Filters](https://docs.microsoft.com/en-us/aspnet/core/mvc/controllers/filters)
**Filters** in ASP.NET Core allow code to be run *before* or *after* specific stages in the request processing pipeline.
**Filters** in ASP.NET Core allow code to be run _before_ or _after_ specific stages in the request processing pipeline.
Built-in filters handle tasks such as:
@ -11,7 +11,7 @@ Custom filters can be created to handle cross-cutting concerns. Examples of cros
## **How filters work**
Filters run within the *ASP.NET Core action invocation pipeline*, sometimes referred to as the *filter pipeline*. The filter pipeline runs after ASP.NET Core selects the action to execute.
Filters run within the _ASP.NET Core action invocation pipeline_, sometimes referred to as the _filter pipeline_. The filter pipeline runs after ASP.NET Core selects the action to execute.
![filter-pipeline-1](../../.images/dotnet_filter-pipeline-1.png)
![filter-pipeline-2](../../.images/dotnet_filter-pipeline-2.png)
@ -20,18 +20,18 @@ Filters run within the *ASP.NET Core action invocation pipeline*, sometimes ref
Each filter type is executed at a different stage in the filter pipeline:
- **Authorization filters** run first and are used to determine whether the user is authorized for the request. Authorization filters short-circuit the pipeline if the request is not authorized.
- **Authorization filters** run first and are used to determine whether the user is authorized for the request. Authorization filters short-circuit the pipeline if the request is not authorized.
- **Resource filters**:
- Run after authorization.
- `OnResourceExecuting` runs code before the rest of the filter pipeline. For example, `OnResourceExecuting` runs code before model binding.
- `OnResourceExecuting` runs code before the rest of the filter pipeline. For example, `OnResourceExecuting` runs code before model binding.
- `OnResourceExecuted` runs code after the rest of the pipeline has completed.
- **Action filters**:
- Run code immediately before and after an action method is called.
- Can change the arguments passed into an action.
- Can change the result returned from the action.
- Are **not** supported in Razor Pages.
- **Exception filters** apply global policies to unhandled exceptions that occur before the response body has been written to.
- **Result filters** run code immediately before and after the execution of action results. They run only when the action method has executed successfully. They are useful for logic that must surround view or formatter execution.
- Are **not** supported in Razor Pages.
- **Exception filters** apply global policies to unhandled exceptions that occur before the response body has been written to.
- **Result filters** run code immediately before and after the execution of action results. They run only when the action method has executed successfully. They are useful for logic that must surround view or formatter execution.
## **Implementation**
@ -44,7 +44,7 @@ Interfaces for multiple filter stages can be implemented in a single class.
## **Built-in filter attributes**
ASP.NET Core includes built-in *attribute-based* filters that can be subclassed and customized.
ASP.NET Core includes built-in _attribute-based_ filters that can be subclassed and customized.
Several of the filter interfaces have corresponding attributes that can be used as base classes for custom implementations.
Filter attributes:
@ -58,12 +58,12 @@ Filter attributes:
## **Filter scopes**
A filter can be added to the pipeline at one of three *scopes*:
A filter can be added to the pipeline at one of three *scopes*:
- Using an attribute on a controller action. Filter attributes cannot be applied to Razor Pages handler methods.
```cs
// services.AddScoped<CustomActionFilterAttibute>();
// services.AddScoped<CustomActionFilterAttribute>();
[ServiceFilter(typeof(CustomActionFilterAttribute))]
public IActionResult Index()
{
@ -101,14 +101,14 @@ public void ConfigureServices(IServiceCollection services)
When there are multiple filters for a particular stage of the pipeline, scope determines the default order of filter execution. Global filters surround class filters, which in turn surround method filters.
As a result of filter nesting, the *after* code of filters runs in the reverse order of the *before* code. The filter sequence:
As a result of filter nesting, the *after* code of filters runs in the reverse order of the *before* code. The filter sequence:
- The *before* code of global filters.
- The *before* code of controller and Razor Page filters.
- The *before* code of action method filters.
- The *after* code of action method filters.
- The *after* code of controller and Razor Page filters.
- The *after* code of global filters.
- The *before* code of global filters.
- The *before* code of controller and Razor Page filters.
- The *before* code of action method filters.
- The *after* code of action method filters.
- The *after* code of controller and Razor Page filters.
- The *after* code of global filters.
### Cancellation and Short-Circuiting

16
DotNet/ASP.NET/MVC.md
View file

@ -42,7 +42,7 @@ Project
| |-HomeController.cs
|
|- appsettings.json
|- Program.cs --> App entrypoiny
|- Program.cs --> App entry-point
|- Startup.cs --> App config
```
@ -70,7 +70,7 @@ namespace App.Controllers
// GET /Controller/Index
public IActionResult Index()
{
IEnumerable<Entity> enities = _db.Entities;
IEnumerable<Entity> entities = _db.Entities;
return View(Entities); // pass data to the @model
}
@ -83,7 +83,7 @@ namespace App.Controllers
// POST /Controller/Create
[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult Create(Entity entity) // recieve data from the @model
public IActionResult Create(Entity entity) // receive data from the @model
{
_db.Entities.Add(entity);
_db.SaveChanges();
@ -104,7 +104,7 @@ namespace App.Controllers
return NotFound();
}
return View(entity); // return pupulated form for updating
return View(entity); // return populated form for updating
}
// POST /Controller/Edit
@ -136,7 +136,7 @@ namespace App.Controllers
return NotFound();
}
return View(entity); // return pupulated form for confirmation
return View(entity); // return populated form for confirmation
}
// POST /Controller/Delete
@ -197,7 +197,7 @@ In `View.cshtml`;
<div class="col-8">
<input asp-for="IntProp" class="form-control"/>
<span asp-validation-for="IntProp" class="text-danger"></span> // error message displyed here
<span asp-validation-for="IntProp" class="text-danger"></span> // error message displayed here
</div>
</div>
</form>
@ -230,7 +230,7 @@ namespace App.Controllers
// GET /Controller/Index
public IActionResult Index()
{
IEnumerable<Entity> enities = _db.Entities;
IEnumerable<Entity> entities = _db.Entities;
return View(Entities); // pass data to the @model
}
@ -243,7 +243,7 @@ namespace App.Controllers
// POST /Controller/Create
[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult Create(Entity entity) // recieve data from the @model
public IActionResult Create(Entity entity) // receive data from the @model
{
if (ModelState.IsValid) // all rules in model have been met
{

14
DotNet/ASP.NET/Middleware.md
View file

@ -7,13 +7,13 @@ Middleware is software that's assembled into an app pipeline to handle requests
Request delegates are used to build the request pipeline. The request delegates handle each HTTP request.
Request delegates are configured using [Run][Run_docs], [Map][Map_docs], and [Use][Use_docs] extension methods.
Request delegates are configured using [Run][Run_docs], [Map][Map_docs], and [Use][Use_docs] extension methods.
An individual request delegate can be specified in-line as an anonymous method (called in-line middleware), or it can be defined in a reusable class.
These reusable classes and in-line anonymous methods are *middleware*, also called *middleware components*.
These reusable classes and in-line anonymous methods are *middleware*, also called *middleware components*.
Each middleware component in the request pipeline is responsible for invoking the next component in the pipeline or short-circuiting the pipeline.
When a middleware short-circuits, it's called a *terminal middleware* because it prevents further middleware from processing the request.
When a middleware short-circuits, it's called a *terminal middleware* because it prevents further middleware from processing the request.
[Use_docs]: https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.builder.useextensions.use
[Run_docs]: https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.builder.runextensions.run
@ -166,10 +166,10 @@ namespace <App>
The middleware class **must** include:
- A public constructor with a parameter of type [RequestDelegate][RequestDelegate_docs].
- A public method named `Invoke` or `InvokeAsync`. This method must:
- Return a `Task`.
- Accept a first parameter of type [HttpContext][HttpConrext_Docs].
- A public constructor with a parameter of type [RequestDelegate][RequestDelegate_docs].
- A public method named `Invoke` or `InvokeAsync`. This method must:
- Return a `Task`.
- Accept a first parameter of type [HttpContext][HttpConrext_Docs].
[RequestDelegate_docs]: https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.http.requestdelegate
[HttpConrext_Docs]: https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.http.httpcontext

6
DotNet/ASP.NET/REST API.md
View file

@ -2,8 +2,8 @@
## Data Transfer Objects (DTOs)
A **DTO** is an object that defines how the data will be sent and recieved over the network (usually as JSON).
Without a DTO the JSON response (or reqest) could contain irrilevant, wrong or unformatted data.
A **DTO** is an object that defines how the data will be sent and received over the network (usually as JSON).
Without a DTO the JSON response (or request) could contain irrelevant, wrong or unformatted data.
Moreover, by decoupling the JSON response from the actual data model, it's possible to change the latter without breaking the API.
DTOs must be mapped to the internal methods.
@ -50,7 +50,7 @@ namespace <Namespace>.Profiles
## Controller (No View)
Uses [Dependency Injection](https://en.wikipedia.org/wiki/Dependency_injection) to recieve a suitable implementation of `IEntityRepo`,
Uses [Dependency Injection](https://en.wikipedia.org/wiki/Dependency_injection) to receive a suitable implementation of `IEntityRepo`,
### Service Lifetimes

14
DotNet/ASP.NET/Razor Pages.md
View file

@ -33,7 +33,7 @@ Project
| |- ...
|
|- appsettings.json --> application settings
|- Program.cs --> App entrypoint
|- Program.cs --> App entry-point
|- Startup.cs
```
@ -88,17 +88,17 @@ namespace App.Pages
{
private readonly ApplicationDbContext _db; // EF DB Context
// Get DBContex through DI
// Get DBContext through DI
public IndexModel(ApplicationDbContext db)
{
_db = db;
}
[BindProperty] // assumed to be recieved on POST
[BindProperty] // assumed to be received on POST
public IEnumerable<Entity> Entities { get; set; }
// HTTP Method Handler
public aysnc Task OnGet()
public async Task OnGet()
{
// get data from DB (example operation)
Entities = await _db.Entities.ToListAsync();
@ -131,12 +131,12 @@ Rules:
- URL maps to a physical file on disk
- Razor paged needs a root folder (Default "Pages")
- file extension not included in URL
- `Index.cshtml` is enrtypoint and default document (missing file in URL redirects to index)
- `Index.cshtml` is entry-point and default document (missing file in URL redirects to index)
| URL | Maps TO |
|------------------------|----------------------------------------------------|
| www.domain.com | /Pages/Index.cshtml |
| www.doamin.com/Index | /Pages/Index.html |
| www.domain.com/Index | /Pages/Index.html |
| www.domain.com/Account | /Pages/Account.cshtml, /Pages/Account/Index.cshtml |
## Data Validation
@ -179,7 +179,7 @@ In `View.cshtml`;
<div class="col-8">
<input asp-for="IntProp" class="form-control"/>
<span asp-validation-for="IntProp" class="text-danger"></span> // error message displyed here
<span asp-validation-for="IntProp" class="text-danger"></span> // error message displayed here
</div>
</div>
</form>

12
DotNet/ASP.NET/Razor Syntax.md
View file

@ -10,14 +10,14 @@
@* razor comment *@
// substituite @variable with it's value
// substitute @variable with it's value
<tag>@variable</tag>
@{
// razor code block
// can contain C# or HTML
Model // acces to passed @model (MVC)
Model // access to passed @model (MVC)
}
@if (condition) { }
@ -58,7 +58,7 @@ The first parameter after `@addTagHelper` specifies the Tag Helpers to load (`*`
It's possible to disable a Tag Helper at the element level with the Tag Helper opt-out character (`!`)
```cshtml
<!-- disable email vaidation -->
<!-- disable email validation -->
<!span asp-validation-for="Email" ></!span>
```
@ -86,7 +86,7 @@ The `@tagHelperPrefix` directive allows to specify a tag prefix string to enable
@Model.EntityProp
<from>
// use the property as the label, eventyally w/ [DysplayName("...")]
// use the property as the label, eventually w/ [DisplayName("...")]
<label asp-for="EntityProp"></label>
@Html.LabelFor()
@ -131,7 +131,7 @@ In `View.cs`
<form asp-controller="Controller" asp-action="PostAction">
<select asp-for"EntityId" asp-items="Model.Enities">
<select asp-for"EntityId" asp-items="Model.Entities">
</select>
<button type="submit">Send<button>
@ -145,7 +145,7 @@ public IActionResult GetAction()
{
var vm = new ViewModel();
vm.Entities = new SelectList(_context.Enities, "Id", "Text"); // fill SelectList
vm.Entities = new SelectList(_context.Entities, "Id", "Text"); // fill SelectList
vm.EntityId = value; // set selected option (OPTIONAL)
return View(vm);

6
DotNet/ASP.NET/SignalR.md
View file

@ -52,9 +52,9 @@ public class CustomHub : Hub
return Clients.Caller.SendAsync("CLientMethod", args);
// trigger function on clients of a group and pass args to it
return Clients.Group("GoupName").SendAsync("CLientMethod", args);
return Clients.Group("GroupName").SendAsync("CLientMethod", args);
// other opeations
// other operations
}
}
```
@ -149,7 +149,7 @@ Reference the SignalR JavaScript client in the `<script>` element. For example:
const connection = new signalR.HubConnectionBuilder()
.withUrl("/hub/endpoint")
.configureLogging(signalR.LogLevel.Information)
.withAutomaticreconnect() // optional
.withAutomaticReconnect() // optional
.build();
// async/await connection start

4
DotNet/ASP.NET/WebForms.md
View file

@ -2,7 +2,7 @@
## `Page.aspx`
The fist loaded page is `Default.aspx` and its undelying code.
The fist loaded page is `Default.aspx` and its underlying code.
```html
<!-- directive -->
@ -76,7 +76,7 @@ namespace Project
}
protected void Control_Event(object sender, EventAtgs e)
protected void Control_Event(object sender, EventArgs e)
{
// actions on event trigger
}

2
DotNet/ASP.NET/WebForms/Page.aspx.cs.md
View file

@ -17,7 +17,7 @@ namespace Project
}
protected void Control_Event(object sender, EventAtgs e)
protected void Control_Event(object sender, EventArgs e)
{
// actions on event trigger
}

4
DotNet/ASP.NET/WebForms/Page.aspx.md
View file

@ -1,6 +1,6 @@
# Page.aspx
The fist loaded page is `Default.aspx` and its undelying code.
The fist loaded page is `Default.aspx` and its underlying code.
```html
<!-- directive -->
@ -38,7 +38,7 @@ The fist loaded page is `Default.aspx` and its undelying code.
```xml
<asp:Control ID="" runat="server" ...></asp:Control>
<!-- Label: empty text will diplay ID, use empty space as text for empty label -->
<!-- Label: empty text will display ID, use empty space as text for empty label -->
<asp:Label ID="lbl_" runat="server" Text=" "></asp:Label>
<!-- TextBox -->
<asp:TextBox ID="txt_" runat="server"></asp:TextBox>

40
DotNet/C#/C# Collections.md
View file

@ -2,9 +2,9 @@
## Arrays
An array is an object that contains multiple elements of a particular type. The number of elements is fixed for the lifetime of the array, so it must be specied when the array is created.
An array is an object that contains multiple elements of a particular type. The number of elements is fixed for the lifetime of the array, so it must be specified when the array is created.
An array type is always a reference type, regardless of the element type. Nonetheless, the choice between reference type and value type elements makes a significant difference in an array’s behavior.
An array type is always a reference type, regardless of the element type. Nonetheless, the choice between reference type and value type elements makes a significant difference in an array's behavior.
```cs
type[] array = new type[dimension];
@ -14,9 +14,9 @@ type[] array = {value1, value2, ..., valueN}; // initializer
var array = new type[] {value1, value2, ..., valueN}; // initializer (var type needs new operator)
var array = new[] {value1, value2, ..., valueN}; // initializer w/ element type inference (var type needs new operator), can be used as method arg
array[index]; // value acces
array[index] = value; // value assignement
array.Lenght; // dimension of the array
array[index]; // value access
array[index] = value; // value assignment
array.Length; // dimension of the array
// from IEnumerable<T>
array.OfType<Type>(); // filter array based on type, returns IEnumerable<Type>
@ -27,17 +27,17 @@ array.OfType<Type>(); // filter array based on type, returns IEnumerable<Type>
```cs
// overloaded search methods
Array.IndexOf(array, item); // return index of searched item in passed array
Array.LastIndexOf(array, item); // return index of searched item staring from the end of the arrary
Array.LastIndexOf(array, item); // return index of searched item staring from the end of the array
Array.FindIndex(array, Predicate<T>) // returns the index of the first item matching the predicate (can be lambda function)
Array.FindLastIndex(array, Predicate<T>) // returns the index of the last item matching the predicate (can be lambda function)
Array.Find(array, Predicate<T>) // returns the value of the first item matching the predicate (can be lambda function)
Array.FindLast(array, Predicate<T>) // returns the value of the last item matvhing the predicate (can be lambda function)
Array.FindLast(array, Predicate<T>) // returns the value of the last item matching the predicate (can be lambda function)
Array.FindAll(array, Predicate<T>) // returns array of all items matching the predicate (can be lambda function)
Array.BinarySearch(array, value) // Searches a SORTED array for a value, using a binary search algorithm; retuns the index of the found item
Array.BinarySearch(array, value) // Searches a SORTED array for a value, using a binary search algorithm; returns the index of the found item
Array.Sort(array);
Array.Reverse(array); // reverses the order of array elements
Array.Clear(start_index, x); //removes reference to x elements starting at start index. Dimension of array uncanged (cleared elements value is set tu null)
Array.Clear(start_index, x); //removes reference to x elements starting at start index. Dimension of array unchanged (cleared elements value is set tu null)
Array.Resize(ref array, target_dimension); //expands or shrinks the array dimension. Shrinking drops trailing values. Array passed by reference.
// Copies elements from an Array starting at the specified index and pastes them to another Array starting at the specified destination index.
@ -78,8 +78,8 @@ type[,] matrix = new type[n, m]; // n * m matrix
type[,] matrix = {{}, {}, {}, ...}; // {} for each row to initialize
type[, ,] tensor = new type[n, m, o] // n * m * o tensor
matrix.Length; // total numeber of elements (n * m)
matrix.GetLenght(int dimension); // get the size of a particular direction
matrix.Length; // total number of elements (n * m)
matrix.GetLength(int dimension); // get the size of a particular direction
// row = 0, column = 1, ...
```
@ -102,13 +102,13 @@ list.Insert(index, item); // insert an item at the specified index
list.InsertRange(index, item); // insert items at the specified index
list.IndexOf(item); // return index of searched item in passed list
list.LastIndexOf(item); // return index of searched item staring from the end of the arrary
list.LastIndexOf(item); // return index of searched item staring from the end of the array
list.FindIndex(Predicate<T>) // returns the index of the first item matching the predicate (can be lambda function)
list.FindLastIndex(Predicate<T>) // returns the index of the last item matching the predicate (can be lambda function)
list.Find(Predicate<T>) // returns the value of the first item matching the predicate (can be lambda function)
list.FindLast(Predicate<T>) // returns the value of the last item matvhing the predicate (can be lambda function)
list.FindLast(Predicate<T>) // returns the value of the last item matching the predicate (can be lambda function)
list.FindAll(Predicate<T>) // returns list of all items matching the predicate (can be lambda function)
list.BinarySearch(value) // Searches a SORTED list for a value, using a binary search algorithm; retuns the index of the found item
list.BinarySearch(value) // Searches a SORTED list for a value, using a binary search algorithm; returns the index of the found item
list.Remove(item); // remove item from list
list.RemoveAt(index); // remove item at specified position
@ -138,7 +138,7 @@ When a `yield return` statement is reached, the current location in code is reme
It's possible to use a `yield break` statement or exception to end the iteration.
**Note**: Since an iteartor returns an `IEnumerable<T>` is can be used to implement a `GetEnumerator()`.
**Note**: Since an iterator returns an `IEnumerable<T>` is can be used to implement a `GetEnumerator()`.
```cs
// simple iterator
@ -159,7 +159,7 @@ Exposes the enumerator, which supports a simple iteration over a collection of a
```cs
public interface IEnumerable<out T> : IEnumerable
{
IEnumerator<T> GetEnumerator(); // retrun an enumerator
IEnumerator<T> GetEnumerator(); // return an enumerator
}
// iterate through a collection
@ -227,7 +227,7 @@ Span<T> slice = array[start..end];
ReadOnlySpan<T> slice = array[start..end];
```
## [Dictioanaries](https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2)
## [Dictionaries](https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2)
[ValueCollection](https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2.valuecollection)
[KeyCollection](https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2.keycollection)
@ -258,10 +258,10 @@ Dictionary<TKey, TValue> dict =
}
// indexer access
dict[key]; // read value associted with key (throws KeyNotFoundException if key does not exist)
dict[key] = value; // modify value associted with key (throws KeyNotFoundException if key does not exist)
dict[key]; // read value associated with key (throws KeyNotFoundException if key does not exist)
dict[key] = value; // modify value associated with key (throws KeyNotFoundException if key does not exist)
dict.Count; // numer of key-value pair stored in the dict
dict.Count; // number of key-value pair stored in the dict
dict.Keys; // Dictionary<TKey,TValue>.KeyCollection containing the keys of the dict
dict.Values; // Dictionary<TKey,TValue>.ValueCollection containing the values of the dict

10
DotNet/C#/LINQ.md
View file

@ -11,7 +11,7 @@ LINQ to Objects will be used when any `IEnumerable<T>` is specified as the sourc
### Query Expressions
All query expressions are required to begin with a `from` clause, which specifies the source of the query.
The final part of the query is a `select` (or `group`) clause. This determines the final output of the query and its sytem type.
The final part of the query is a `select` (or `group`) clause. This determines the final output of the query and its system type.
```cs
// query expression
@ -21,10 +21,10 @@ var result = from item in enumerable select item;
var result = from item in enumerable where condition select item;
// ordering
var result = from item in enumerable orderby item.property select item; // ordered IEnumerble
var result = from item in enumerable orderby item.property select item; // ordered IEnumerable
// let clause, assign expression to variable to avoid re-evaluetion on each cycle
var result = from item in enumerable let tmp = <sub-expr> ... // BEWARE: compiled code has a lot of overhead to satisfy let caluse
// let clause, assign expression to variable to avoid re-evaluation on each cycle
var result = from item in enumerable let tmp = <sub-expr> ... // BEWARE: compiled code has a lot of overhead to satisfy let clause
// grouping (difficult to re-implement to obtain better performance)
var result = from item in enumerable group item by item.property; // returns IEnumerable<IGrouping<TKey,TElement>>
@ -63,7 +63,7 @@ IEnumerable<T>.Any(Func<T, bool> predicate); // check if condition is true for
IEnumerable<T>.Concat(IEnumerable<T> enumerable);
// Applies a specified function to the corresponding elements of two sequences, producing a sequence of the results.
IEnumerable<TFirst>.Zip(IEnumerable<TSecond> enumerable, Func<TFirst, TSecoind, TResult> func);
IEnumerable<TFirst>.Zip(IEnumerable<TSecond> enumerable, Func<TFirst, TSecond, TResult> func);
IEnumerable<TFirst>.Zip(IEnumerable<TSecond> enumerable); // Produces a sequence of tuples with elements from the two specified sequences.
```

2
DotNet/C#/Reactive Extensions.md
View file

@ -3,7 +3,7 @@
The **Reactive Extensions** for .NET, or **Rx**, are designed for working with asynchronous and event-based sources of information.
Rx provides services that help orchestrate and synchronize the way code reacts to data from these kinds of sources.
Rx’s fundamental abstraction, `IObservable<T>`, represents a sequence of items, and its operators are defined as extension methods for this interface.
Rx's fundamental abstraction, `IObservable<T>`, represents a sequence of items, and its operators are defined as extension methods for this interface.
This might sound a lot like LINQ to Objects, and there are similarities, not only does `IObservable<T>` have a lot in common with `IEnumerable<T>`, but Rx also supports almost all of the standard LINQ operators.

6
DotNet/Database/ADO.NET.md
View file

@ -22,7 +22,7 @@ The `ADO.NET` classes are found in `System.Data.dll`, and are integrated with th
### [SQLite](https://www.connectionstrings.com/sqlite/)
- Basic: `Data Source: path\to\db.sqlite3; Version=3;`
- In-Memory Dataabse: `Data Source=:memory:; Version=3; New=True`
- In-Memory Database: `Data Source=:memory:; Version=3; New=True`
- With Password: `Data Source: path\to\db.sqlite3; Version=3; Password=<password>`
## Connection to DB
@ -59,7 +59,7 @@ namespace <namespace>
using (SqlConnection connection = new SqlConnection())
{
connection.ConnectionString = connectionString.ConnectionString;
connection.Open(); // start comunication w/ sql server
connection.Open(); // start communication w/ sql server
}
// more compact
@ -106,7 +106,7 @@ using (SqlDataReader cursor = command.ExecuteReader()) // object to get data fr
// check for null before retrieving the value
if(!cursor.IsDBNull(n))
{
sqlreader.Get<SystemType>(index); // retrieve data form the n-th column
cursor.Get<SystemType>(index); // retrieve data form the n-th column
}
}
}

2
DotNet/Database/EntityFramework.md
View file

@ -67,7 +67,7 @@ namespace <Project>.Model
Create & Update DB Schema if necessary.
In Packge Manager Shell:
In Package Manager Shell:
```ps1
PM> Add-Migration <migration_name>

28
DotNet/Unity/Collisions.md
View file

@ -2,14 +2,14 @@
## Rigidbody Component
Enables physycs on the game objects.
Enables physics on the game objects.
Rigidbodies collide with other objects instead of going through them.
Avoid obejct rotation on colisions:
Avoid object rotation on collisions:
1. Assign `Rigidbody` component to object
2. Enable Freeze Rotaion in Rigidbody > Constraints
2. Enable Freeze Rotation in Rigidbody > Constraints
```cs
using UnityEngine;
@ -21,19 +21,19 @@ public class GameObject : MonoBehaviour {
void Start()
{
rigidbody = GetComponenet<Rigidbody>(); // get rigidbody reference
rigidbody = GetComponent<Rigidbody>(); // get rigidbody reference
}
void Update()
{
}
// FixedUpdate is calles every x seconds (not influenced by FPS instability)
// used for physics calculations which sould be FPS independant
// FixedUpdate is calls every x seconds (not influenced by FPS instability)
// used for physics calculations which should be FPS independent
void FixedUpdate()
{
Time.fixedDeltaTime; // fixed amount of time
Time.timeDelta; // if called inside FIxedUpadate() behaves like fixedDeltaTime
Time.timeDelta; // if called inside FIxedUpdate() behaves like fixedDeltaTime
}
}
@ -44,8 +44,8 @@ public class GameObject : MonoBehaviour {
Enable `Is Trigger` to register the collision but avoid blocking the movement of the objects.
The trigger can generate a event to signal the contact with the object.
One of the collidng GameObjects *must have* the `Rigidbody` component and the other `Is Trigger` enabled.
To detect the collison but avoid computing the physycs `Is Kinematic` must be enabled in the `Rigidbody` component.
One of the colliding GameObjects *must have* the `Rigidbody` component and the other `Is Trigger` enabled.
To detect the collision but avoid computing the physics `Is Kinematic` must be enabled in the `Rigidbody` component.
```cs
using UnityEngine;
@ -57,21 +57,21 @@ public class GameObject : MonoBehaviour {
void Start()
{
rigidbody = GetComponenet<Rigidbody>(); // get rigidbody reference
rigidbody = GetComponent<Rigidbody>(); // get rigidbody reference
}
// FixedUpdate is calles every x seconds (not influenced by FPS instability)
// used for physics calculations which sould be FPS independant
// FixedUpdate is calls every x seconds (not influenced by FPS instability)
// used for physics calculations which should be FPS independent
void FixedUpdate()
{
Time.fixedDeltaTime; // fixed amount of time
Time.timeDelta; // if called inside FIxedUpadate() behaves like fixedDeltaTime
Time.timeDelta; // if called inside FixedUpdate() behaves like fixedDeltaTime
}
// called on box collision.
void OnTriggerEnter(Collider triggerCollider) {
// detect a collison with a perticular GameObject(must have a TAG)
// detect a collision with a particular GameObject(must have a TAG)
if (triggerCollider.tag = "tag") {
Destroy(triggerCollider.gameObject); // destroy tagged item on collision
//or

4
DotNet/Unity/Coroutines.md
View file

@ -2,7 +2,7 @@
[Coroutines - Unity manual](https://docs.unity3d.com/Manual/Coroutines.html)
When you call a function, it runs to completion before returning. This effectively means that any action taking place in a function must happen *within a single frame update*; a function call can’t be used to contain a procedural animation or a sequence of events over time.
When you call a function, it runs to completion before returning. This effectively means that any action taking place in a function must happen *within a single frame update*; a function call can't be used to contain a procedural animation or a sequence of events over time.
A coroutine is like a function that has the ability to pause execution and return control to Unity but then to continue where it left off on the following frame.
@ -22,7 +22,7 @@ IEnumerator coroutine()
// or
yeld return StartCoroutine(coroutine()); // wait for anothe coroitine to finish before starting
yeld return StartCoroutine(coroutine()); // wait for another coroutine to finish before starting
}
StartCoroutine(coroutine()); // start the coroutine

6
DotNet/Unity/Input Manager.md
View file

@ -4,7 +4,7 @@ The Input Manager uses the following types of controls:
- **Key** refers to any key on a physical keyboard, such as `W`, `Shift`, or the `space bar`.
- **Button** refers to any button on a physical controller (for example, gamepads), such as the `X` button on an Xbox One controller.
- A **virtual axis** (plural: axes) is mapped to a **control**, such as a button or a key. When the user activates the control, the axis receives a value in the range of `[–1..1]`.
- A **virtual axis** (plural: axes) is mapped to a **control**, such as a button or a key. When the user activates the control, the axis receives a value in the range of `[-1..1]`.
## Virtual axes
@ -30,8 +30,8 @@ The Input Manager uses the following types of controls:
Axis values can be:
- Between `–1` and `1` for joystick and keyboard input. The neutral position for these axes is `0`. Some types of controls, such as buttons on a keyboard, aren’t sensitive to input intensity, so they can’t produce values other than `–1`, `0`, or `1`.
- Mouse delta (how much the mouse has moved during the last frame) for mouse input. The values for mouse input axes can be larger than `1` or smaller than `–1` when the user moves the mouse quickly.
- Between `-1` and `1` for joystick and keyboard input. The neutral position for these axes is `0`. Some types of controls, such as buttons on a keyboard, aren't sensitive to input intensity, so they can't produce values other than `-1`, `0`, or `1`.
- Mouse delta (how much the mouse has moved during the last frame) for mouse input. The values for mouse input axes can be larger than `1` or smaller than `-1` when the user moves the mouse quickly.
```cs
//Define the speed at which the object moves.

4
DotNet/Unity/Prefabs Instantiation.md
View file

@ -1,8 +1,8 @@
# Prefabs
Prefabs are a blueprint for GameObcets and any change made to the prefab is inherited by all it's instances.
Prefabs are a blueprint for GameObjects and any change made to the prefab is inherited by all it's instances.
## Script Instantation
## Script Instantiation
```cs

20
DotNet/Unity/Raycasting.md
View file

@ -1,6 +1,6 @@
# Raycasting Notes
A raycast is conceptually like a laser beam that is fired from a point in space along a particular directuin. Any object making contact with the beam can be detected and reported.
A raycast is conceptually like a laser beam that is fired from a point in space along a particular direction. Any object making contact with the beam can be detected and reported.
## 3D Raycasting
@ -16,13 +16,13 @@ void Update()
hitInfo.transform // transform og the hit object
hitInfo.collider.gameObject // reference to the object hit by the ray
hitInfo.collider.gameObject // reference to the object hit by the ray
hitInfo.normal // normal bector og the hit surface
hitInfo.normal // normal vector og the hit surface
hitInfo.point // actual point of collision
// static method, object must haave a collider dot the collision to happen, returns a BOOL
// static method, object must have a collider dot the collision to happen, returns a BOOL
Physics.Raycast(ray, out hitInfo); // update hitInfo based on ray collisions
Physics.Raycast(ray, out hitInfo, float maxRayDistance); // limit the ray length
Physics.Raycast(ray, out hitInfo, Mask mask); // specify with which layers the ray can interact, layer must be allpied to object's mask
Physics.Raycast(ray, out hitInfo, Mask mask); // specify with which layers the ray can interact, layer must be applied to object's mask
Physics.Raycast(ray, out hitInfo, Mask mask, QueryTriggerInteraction.Ignore); // ignore collision if "is trigger" is enabled on other objects
// detect a collision
@ -30,12 +30,12 @@ void Update()
{
//collision happened
// draw the ray ingame for debuggng
// draw the ray in game for debugging
Debug.DrawLine(ray.origin, hitInfo.point, Color.red); // draw red line if collision happens
}
else
{
Debug.DrawLine(ray.origin, ray.origin + ray.direction * 100, Color.blue); // draw blue line if collision happens, arrival point is 100 units from the origin sinche the ray goes to infinity
Debug.DrawLine(ray.origin, ray.origin + ray.direction * 100, Color.blue); // draw blue line if collision happens, arrival point is 100 units from the origin since the ray goes to infinity
}
}
```
@ -47,8 +47,8 @@ public Camera gameCamera;
void Update()
{
// ray goint ftom cametra through a screen point
Ray ray = gameCamera.ScreenPointToRay(Input.mousePosition); // Input.mousePosition is the postion of the mouse in pixels (screen points)
// ray going from camera through a screen point
Ray ray = gameCamera.ScreenPointToRay(Input.mousePosition); // Input.mousePosition is the position of the mouse in pixels (screen points)
RaycastHit hitInfo; // place pointed by the mouse
Physics.Raycast(ray, out hitInfo) // update pointed position
@ -61,12 +61,12 @@ void Update()
void Start()
{
Physisc2D.queriesStartColliders = false; // avoid collision with collider of the ray generator gameObject
Physics2D.queriesStartColliders = false; // avoid collision with collider of the ray generator gameObject
}
void Update()
{
// returns a RaycastHit2D, needs an origin and direction separatedly
// returns a RaycastHit2D, needs an origin and direction separately
Raycast2D hitInfo = Physics2D.Raycast(Vector2 origin, Vector2 direction);
Raycast2D hitInfo = Physics2D.Raycast(Vector2 origin, Vector2 direction, float maxRayDistance);
Raycast2D hitInfo = Physics2D.Raycast(Vector2 origin, Vector2 direction, float maxRayDistance);

28
DotNet/Unity/Scripting.md
View file

@ -24,25 +24,25 @@ public class ClassName : MonoBehaviour {
Time.deltaTime; // time since last frame
}
// FixedUpdate is calles every x seconds (not influenced by FPS instability)
// used for physics calculations which sould be FPS independant
// FixedUpdate is calls every x seconds (not influenced by FPS instability)
// used for physics calculations which should be FPS independent
void FixedUpdate()
{
Time.fixedDeltaTime; // fixed amount of time
Time.timeDelta; // if called inside FIxedUpadate() behaves like fixedDeltaTime
Time.timeDelta; // if called inside FIxedUpdate() behaves like fixedDeltaTime
}
}
```
### Script comunication
### Script communication
Referencing data in a sctipt from another.
Referencing data in a script from another.
```cs
//example of a script to be referenced in another
Using System;
public class Player : MonoBheaviour {
public class Player : MonoBehaviour {
public float health = 10;
public event Action OnPlayerDeath; //event of type Action, needs using System
@ -55,7 +55,7 @@ public class Player : MonoBheaviour {
if (health <= 0) {
if (OnPlayerDeath != null) {
OnPleyerDeath(); // invoke Action (if no subscribers event will be NULL, can cause errors)
OnPlayerDeath(); // invoke Action (if no subscribers event will be NULL, can cause errors)
}
Destroy(GameObject); // needs to be notified
@ -68,7 +68,7 @@ public class Player : MonoBheaviour {
// example of script needing a reference to another
public class GameUI : MonoBehaviour {
Player player; //instance of referenced GameObject to be founf by its type
Player player; //instance of referenced GameObject to be found by its type
void Start(){
GameObject playerObj = GameObject.Find("Player"); //reference to game object
@ -77,7 +77,7 @@ public class GameUI : MonoBehaviour {
player = FindObjectOfType<Player>(); // get reference to an object
// on event invocation all subscribet methods will be called
// on event invocation all subscriber methods will be called
player.OnPlayerDeath += GameOver; // subscribe method to event
}
@ -85,7 +85,7 @@ public class GameUI : MonoBehaviour {
DrawHealthBar(plyer.health); // call method passing data of player GameObject
}
void DrawHealthbar(float playerHealth) {
void DrawHealthBar(float playerHealth) {
// implementation
}
@ -100,9 +100,9 @@ public class GameUI : MonoBehaviour {
### 2D Screen Measures
Aspect Ratio = `(screen_width [px]) / (screen_height [px])`
Orhograpic Size `[world units]` = `(screen_height [world units] / 2)`
Aspect Ratio * Orhograpic Size = `(screen_width [world units] / 2)`
Screen Width `[world units]` = `(AspectRatio * OrhograpicSize * 2)`
Orthographic Size `[world units]` = `(screen_height [world units] / 2)`
Aspect Ratio * Orthographic Size = `(screen_width [world units] / 2)`
Screen Width `[world units]` = `(AspectRatio * OrthographicSize * 2)`
```cs
screenWidth = Camera.main.aspect * Camera.main.orthographicSize * 2;
@ -123,7 +123,7 @@ public class ScriptableObjectName : ScriptableObject {
### Game Object Serialization
```c#
[SeralizeField] type variable; //access game object from code
[SerializeField] type variable; //access game object from code
```
### Game Object Data Access

22
DotNet/Unity/Vector, Tranfrorm, Space.md
View file

@ -1,4 +1,4 @@
# Vector, Tranfrorm, Space
# Vector, Transform, Space
## Vector2, Vector3, Vector4
@ -33,8 +33,8 @@ Vector3.one // Vector3(1, 1, 1)
### Operations
```cs
Vector3(x, y, z) * n = Vecotr3(xn, yn, yz);
Vector3(x, y, z) / n = Vecotr3(x / n, y / n, y / z);
Vector3(x, y, z) * n = Vector3(xn, yn, yz);
Vector3(x, y, z) / n = Vector3(x / n, y / n, y / z);
Vector3(x1, y1, z1) + Vector3(x2, y2, z2) = Vector3(x1 + x2, y1 + y2, z1 + z2);
Vector3(x1, y1, z1) - Vector3(x2, y2, z2) = Vector3(x1 - x2, y1 - y2, z1 - z2);
@ -54,11 +54,11 @@ MovementInFrame = Speed * timeSinceLastFrame
[Transform Docs](https://docs.unity3d.com/ScriptReference/Transform.html)
```cs
// propetries
transfrom.position // Vector3 - global position
transfrom.localPosition // Vector3 - local position
// properties
transform.position // Vector3 - global position
transform.localPosition // Vector3 - local position
transform.rotation // Quaternion - global rotation
transfrom.parent // Transform - parent of the object
transform.parent // Transform - parent of the object
transform.localScale = Vector3; // set object dimensions
@ -67,21 +67,21 @@ transform.Rotate(Vector3 * Time.deltaTime * speed, Space); // set rotation usin
transform.Translate(Vector3 * Time.deltaTime * speed, Space); // set movement in selected space
```
### Local, GLobal & Object Spcace
### Local, GLobal & Object Space
**Local Space**: Applies transformation relative to the *local* coordinate system (`Space.Self`).
**Global Space**: Applies transformation relative to the *world* coordinate system (`Space.World`)
### Parenting
Changing the parent will make position, scale and rotation of the child object retalive to the parent but keep the world space's position, rotation and scale the same.
Changing the parent will make position, scale and rotation of the child object relative to the parent but keep the world space's position, rotation and scale the same.
Setting the parentele by script:
```cs
public class ParentScript : MonoBehaviour {
public Transform childTransform; // reference to the child object transfrom
public Transform childTransform; // reference to the child object transform
childTrandform.parent = transfrom; // when evaluated at runtime sets current object as parent of another
childTransform.parent = transform; // when evaluated at runtime sets current object as parent of another
}
```

6
DotNet/Xamarin/App.xaml.md
View file

@ -13,7 +13,7 @@ The word *winfx* refers to a name once used for the .NET Framework 3.0, which in
The `x:Class` attribute can appear only on the root element of a XAML file. It specifies the .NET namespace and name of a derived class. The base class of this derived class is the root element.
In other words, this `x:Class` specification indicates that the `App` class in the `AppName` namespace derives from `Application`.
That’s exactly the same information as the `App` class definition in the `App.xaml.cs` file.
That's exactly the same information as the `App` class definition in the `App.xaml.cs` file.
```xml
<?xml version="1.0" encoding="utf-8" ?>
@ -31,7 +31,7 @@ That’s exactly the same information as the `App` class definition in the `App.
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="AppName.App">
<!-- collection of shared resources definiions -->
<!-- collection of shared resources definitions -->
<Application.Resources>
<!-- Application resource dictionary -->
@ -42,7 +42,7 @@ That’s exactly the same information as the `App` class definition in the `App.
<!-- define a reusable style -->
<Style x:Key="Style Name" TargetType="Element Type">
<!-- set poperties of the style -->
<!-- set properties of the style -->
<Setter Property="PropertyName" Value="PropertyValue">
</Style>

8
DotNet/Xamarin/Page.xaml.md
View file

@ -52,7 +52,7 @@ The term *view* in Xamarin.Forms denotes familiar types of presentation and inte
- StackLayout: Organizes views linearly, either horizontally or vertically.
- AbsoluteLayout: Organizes views by setting coordinates & size in terms of absolute values or ratios.
- RelativeLayout: Organizes views by setting constraints relative to their parent’s dimensions & position.
- RelativeLayout: Organizes views by setting constraints relative to their parent's dimensions & position.
- Grid: Organizes views in a grid of Rows and Columns
- FlexLayout: Organizes views horizontally or vertically with wrapping.
- ScrollView: Layout that's capable of scrolling its content.
@ -60,7 +60,7 @@ The term *view* in Xamarin.Forms denotes familiar types of presentation and inte
### Grid Layout
```xml
<!-- "<num>*" makes the dimesions proportional -->
<!-- "<num>*" makes the dimensions proportional -->
<Gird.RowDefinitions>
<!-- insert a row in the layout -->
<RowDefinition Height="2*"/>
@ -76,11 +76,11 @@ The term *view* in Xamarin.Forms denotes familiar types of presentation and inte
```xml
<Image Source="" BackgroundColor="" [LayoutPosition]/>
<!-- source contains reference to imagefile in Xamarin.[OS]/Resources/drawable -->
<!-- source contains reference to image file in Xamarin.[OS]/Resources/drawable -->
<!-- box to insert text -->
<Editor Placeholder="placeholder text" [LayoutPosition]/>
<!-- clickable button -->
<Button Text="button text" BackgroundColor="" Clicked="function_to_call" [LayoytPosition]/>
<Button Text="button text" BackgroundColor="" Clicked="function_to_call" [LayoutPosition]/>
```

2
DotNet/Xamarin/ViewModel.cs.md
View file

@ -27,7 +27,7 @@ namespace AppName.ViewModels
field = value;
var args = new PropertyChangedEventArgs(nameof(Property)); // EVENT: let view know that the Property has changed
PropertyChanged?.Invoke(this, args); // Ivoke event to notify the view
PropertyChanged?.Invoke(this, args); // Invoke event to notify the view
}
}
}

40
GraphQL.md
View file

@ -50,8 +50,8 @@ GraphQL comes with a set of default scalar types out of the box:
- `Int`: A signed 32‐bit integer.
- `Float`: A signed double-precision floating-point value.
- `String`: A UTF‐8 character sequence.
- `Boolean`: `true` or `false`.
- `ID`: The ID scalar type represents a unique identifier, often used to refetch an object or as the key for a cache. The ID type is serialized in the same way as a `String`; however, defining it as an `ID` signifies that it is not intended to be human‐readable.
- `Boolean`: `true` or `false`.
- `ID`: The ID scalar type represents a unique identifier, often used to refetch an object or as the key for a cache. The ID type is serialized in the same way as a `String`; however, defining it as an `ID` signifies that it is not intended to be human‐readable.
In most GraphQL service implementations, there is also a way to specify custom scalar types.
@ -63,7 +63,7 @@ Then it's up to the implementation to define how that type should be serialized,
### Enumeration Types
Also called *Enums*, enumeration types are a special kind of scalar that is restricted to a particular set of allowed values.
Also called *Enums*, enumeration types are a special kind of scalar that is restricted to a particular set of allowed values.
This allows to:
@ -85,7 +85,7 @@ enum Type{
Object types, scalars, and enums are the only kinds of types that can be defined in GraphQL.
But when used in other parts of the schema, or in the query variable declarations, it's possible apply additional *type modifiers* that affect **validation** of those values.
It's possible to mark a field as *Non-Null* by adding an exclamation mark, `!` after the type name. This means that the server always expects to return a non-null value for this field, and if it ends up getting a null value that will actually trigger a GraphQL execution error, letting the client know that something has gone wrong.
It's possible to mark a field as *Non-Null* by adding an exclamation mark, `!` after the type name. This means that the server always expects to return a non-null value for this field, and if it ends up getting a null value that will actually trigger a GraphQL execution error, letting the client know that something has gone wrong.
The *Non-Null* type modifier can also be used when defining arguments for a field, which will cause the GraphQL server to return a validation error if a null value is passed as that argument, whether in the GraphQL string or in the variables.
@ -190,7 +190,7 @@ It's aldo possible to pass arguments into scalar fields, to implement data trans
### Fragments
Fragments allow to construct sets of fields, and then include them in queries where thay are needed.
Fragments allow to construct sets of fields, and then include them in queries where that are needed.
The concept of fragments is frequently used to split complicated application data requirements into smaller chunks.
```graphql
@ -236,9 +236,9 @@ fragment fragment on Type{
### Operation Name
The *operation type* is either `query`, `mutation`, or `subscription` and describes what type of operation it's intended to be done. The operation type is required unless when using the *query shorthand syntax*, in which case it's not possible to supply a name or variable definitions for the operation.
The *operation type* is either `query`, `mutation`, or `subscription` and describes what type of operation it's intended to be done. The operation type is required unless when using the *query shorthand syntax*, in which case it's not possible to supply a name or variable definitions for the operation.
The *operation name* is a meaningful and explicit name for the operation. It is only required in multi-operation documents, but its use is encouraged because it is very helpful for debugging and server-side logging. When something goes wrong it is easier to identify a query in thecodebase by name instead of trying to decipher the contents.
The *operation name* is a meaningful and explicit name for the operation. It is only required in multi-operation documents, but its use is encouraged because it is very helpful for debugging and server-side logging. When something goes wrong it is easier to identify a query in the codebase by name instead of trying to decipher the contents.
```graphql
query Operation {
@ -250,9 +250,9 @@ query Operation {
When working with variables, three things need to be done:
1. Replace the static value in the query with `$variableName`
2. Declare `$variableName` as one of the variables accepted by the query
3. Pass `variableName: value` in the separate, transport-specific (usually JSON) variables dictionary
1. Replace the static value in the query with `$variableName`
2. Declare `$variableName` as one of the variables accepted by the query
3. Pass `variableName: value` in the separate, transport-specific (usually JSON) variables dictionary
```graphql
query Operation($var: Type = defaultValue) {
@ -275,8 +275,8 @@ A directive can be attached to a field or fragment inclusion, and can affect exe
The core GraphQL specification includes exactly two directives, which must be supported by any spec-compliant GraphQL server implementation:
- `@include(if: Boolean)` Only include this field in the result if the argument is `true`.
- `@skip(if: Boolean)` Skip this field if the argument is `true`.
- `@include(if: Boolean)` Only include this field in the result if the argument is `true`.
- `@skip(if: Boolean)` Skip this field if the argument is `true`.
Server implementations may also add experimental features by defining completely new directives.
@ -299,12 +299,12 @@ mutation Operation {
### Subscriptions
Open a stable connection with the server to recieve real-time updates on the operations happening.
Open a stable connection with the server to receive real-time updates on the operations happening.
```graphql
subscription Operation {
event { # get notified when event happens
field # data recieved on notification
field # data received on notification
...
}
}
@ -349,7 +349,7 @@ GraphQL allows to request `__typename`, a meta field, at any point in a query to
After being validated, a GraphQL query is executed by a GraphQL server which returns a result that mirrors the shape of the requested query, typically as JSON.
Each field on each type is backed by a function called the *resolver* which is provided by the GraphQL server developer. When a field is executed, the corresponding *resolver* is called to produce the next value.
Each field on each type is backed by a function called the *resolver* which is provided by the GraphQL server developer. When a field is executed, the corresponding *resolver* is called to produce the next value.
If a field produces a scalar value like a string or number, then the execution completes. However if a field produces an object value then the query will contain another selection of fields which apply to that object. This continues until scalar values are reached. GraphQL queries always end at scalar values.
@ -358,7 +358,7 @@ If a field produces a scalar value like a string or number, then the execution c
At the top level of every GraphQL server is a type that represents all of the possible entry points into the GraphQL API, it's often called the *Root* type or the *Query* type.
```graphql
# root types for entrypoints
# root types for entry-points
type Query {
rootField(arg: Type = defValue, ...): Type
@ -378,7 +378,7 @@ type Subscription {
A resolver function receives four arguments:
- `obj` The previous object, which for a field on the root Query type is often not used.
- `args` The arguments provided to the field in the GraphQL query.
- `context` A value which is provided to every resolver and holds important contextual information like the currently logged in user, or access to a database.
- `info` A value which holds field-specific information relevant to the current query as well as the schema details
- `obj` The previous object, which for a field on the root Query type is often not used.
- `args` The arguments provided to the field in the GraphQL query.
- `context` A value which is provided to every resolver and holds important contextual information like the currently logged in user, or access to a database.
- `info` A value which holds field-specific information relevant to the current query as well as the schema details

36
HTML/HTML.md
View file

@ -85,7 +85,7 @@ The body contains the actual content of the page. Everything that is contained i
## JavaScript
XHTML and older: `<script src="js/scripts.js" type="text/javascript"></script>`
HTML5: `<script src="js/scripts.js"></script>` (HTML5 spect states that `type` attribute is redundant and shoul be omitted)
HTML5: `<script src="js/scripts.js"></script>` (HTML5 spec states that `type` attribute is redundant and should be omitted)
The `<script>` tag is used to define a client-side script (JavaScript).
The `<script>` element either contains scripting statements, or it points to an external script file through the src attribute.
@ -124,18 +124,18 @@ Uses of Validation:
The application should validate all information to make sure that it is complete, free of errors and conforms to the specifications required by the back-end.
It should contain mechanisms to warn users if input is not complete or correct.
It should avoid to send ‘bad’ data to the back-end.
It should avoid to send "bad" data to the back-end.
### Back-End Validation
It should never trust that the front-end has done validation since some clever users can bypass the front-end mechanisms easily.
Back-end services can receive data from other services, not necessarily front-end, that don’t perform validation.
Back-end services can receive data from other services, not necessarily front-end, that don't perform validation.
#### Built-In Validation
Not all browsers validate in the same way and some follow the specs partially. Some browsers don’t have validation at all (older desktop browsers, some mobile browsers).
Apart from declaring validation intention with HTML5 developers don’t have much control over what the browser actually does.
Before using build-in validation make sure that it’s supported by the target browsers.
Not all browsers validate in the same way and some follow the specs partially. Some browsers don't have validation at all (older desktop browsers, some mobile browsers).
Apart from declaring validation intention with HTML5 developers don't have much control over what the browser actually does.
Before using build-in validation make sure that it's supported by the target browsers.
#### Validation with JavaScript
@ -203,7 +203,7 @@ Heading numbers indicates hierarchy, not size.
<h2> Heading 2 </h2>
```
### Fromatted Text
### Formatted Text
With semantic value:
@ -217,7 +217,7 @@ Without semantic value, used as last resort:
## Elements
`<br/>`: Line break (carriage return). It's not good practice to put line breacks inside paragraphs.
`<br/>`: Line break (carriage return). It's not good practice to put line breaks inside paragraphs.
`<hr>`: horizontal rule (line). Used to define a thematic change in the content.
@ -227,7 +227,7 @@ Surround content to turn into links.
```html
<!-- Link to absolute URL -->
<a href="uri/url" title="content-title" taget="_self"> text/image </a>
<a href="uri/url" title="content-title" target="_self"> text/image </a>
<!-- links to relative URL -->
<a href="//example.com">Scheme-relative URL</a>
@ -282,7 +282,7 @@ Surround content to turn into links.
</ul>
```
### Ordered list (numebred list)
### Ordered list (numbered list)
```html
<ol>
@ -306,8 +306,8 @@ Surround content to turn into links.
```html
<table>
<thead> <!-- table intestation (head) row -->
<th></th> <!-- table intestation, one for each column-->
<thead> <!-- table head row -->
<th></th> <!-- table head, one for each column-->
<th></th>
</thead>
<tbody> <!-- table content (body) -->
@ -323,7 +323,7 @@ Surround content to turn into links.
Code | Character
---------|-----------------
`&copy;` | Copyrigth
`&copy;` | Copyright
`&lt;` | less than (`<`)
`&gt;` | greater than (`>`)
`&amp;` | ampersand (`&`)
@ -361,7 +361,7 @@ Used to apply a specific style inline.
## HTML Forms
```html
<form action="data-reciever" target="" method="http-method">
<form action="data-receiver" target="" method="http-method">
<!-- ALL form elements go here -->
</form>
```
@ -404,7 +404,7 @@ Input Attributes:
* `name`: assigns a name to the form control (used by JavaScript and queries)
* `value`: value to be sent to the server when the option is selected
* `id`: identifier for CSS and linking tags
* `checked`: intially selected or not (radiobutton, checkboxes, ...)
* `checked`: initially selected or not (radiobutton, checkboxes, ...)
* `selected`: default selection of a dropdown
### Text Field
@ -434,7 +434,7 @@ Text inputs can display a placeholder text that will disappear as soon as some t
```html
<form>
<label for="identifier">Password:</label>
<input type="passwrod" name="user-password" id="identifier">
<input type="password" name="user-password" id="identifier">
</form>
```
@ -519,7 +519,7 @@ Multi line text input.
</form>
```
`sumbit`: sends the form data to the location specified in the action attribute.
`submit`: sends the form data to the location specified in the action attribute.
`reset`: resets all forms controls to the default values.
### Button
@ -563,7 +563,7 @@ Downsides:
### Email Field
Used to receive a valid e-mail address from the user. Most browsers can validate this without needing javascript.
Older browsers don’t support this input type.
Older browsers don't support this input type.
```html
<form>

6
Java/DAO.md
View file

@ -67,7 +67,7 @@ public interface I<Type>DAO {
## `<Type>DAO`
Class implementing `I<Type>DAO` and handling the comunication with the db.
Class implementing `I<Type>DAO` and handling the communication with the db.
```java
package dao;
@ -80,8 +80,8 @@ public class <Type>DAO implements I<Type>DAO {
private <Type> results;
private Statement statement; // SQL instruction contenitor
private ResultSet rs; // Query results contenitor
private Statement statement; // SQL instruction container
private ResultSet rs; // Query results container
private DB db;
public <Type>DAO() {

24
Java/Java Collection Framework.md
View file

@ -1,16 +1,16 @@
# Java Collection Framework - JCF
All classes that permit the handling of groups of objects constituite the Java Collection Framework.
All classes that permit the handling of groups of objects constitute the Java Collection Framework.
A Collection is a *container* in which several objects are grouped in a *single entity*.
The **Java Collection Framework** is constituited by:
The **Java Collection Framework** is constituted by:
- **Interfaces** the define the operations of a generic collection. They can be split into two categories:
- **Collection**: used to optimize operations of insertion, modification and deletion of elements in a group of objects.
- **Map**: optimized for look-up operations.
- **Classes** that implement the interfaces using different data structures.
- **Algorithms** consistng in methods to operate over a collection.
- **Algorithms** consisting in methods to operate over a collection.
![Java Collection Hierarchy](../.images/java_java-collection-framework.png "Java Collection Hierarchy")
@ -19,12 +19,12 @@ The **Java Collection Framework** is constituited by:
### Collection Functions
```java
boolean add (Object o) e.g., <x>.add (<y>) //append to colelction, false if fails
boolean add (Object o) e.g., <x>.add (<y>) //append to collection, false if fails
boolean add (int index, Object o) //insertion at given index
boolean addAll (Collection c) //appends a collection to another
void clear() //remove items from container
boolean contains (Object o) //true if object is in collection
boolean containsAll (Collection c) //true if all items of collectio are in another
boolean containsAll (Collection c) //true if all items of collection are in another
boolean isEmpty (Object o) e.g., if (<x>.isEmpty()) ... //true if collection is empty
boolean remove (Object o) //remove object from collection
Object remove (int index) //remove object at given index
@ -60,19 +60,19 @@ ArrayList<Type> ArrayListName = new ArrayList<>(); //resizable array (JAVA 1.
ArrayListName.add(item); //append item to collection
ArrayListName.add(index, item); // add item at positon index, shift all item from index and successive towards the end af the ArrayList
ArrayListName.add(index, item); // add item at position index, shift all item from index and successive towards the end af the ArrayList
ArrayListName.set(index, item); // substitute EXISTING item
ArrayListName.get(index); //access to collection item
ArrayListName.remove(item) //remove first occurence of item from collection
ArrayListName.remove(item) //remove first occurrence of item from collection
ArrayListName.remove(index) //remove item at position index
ArrayListName.clear() //emties the ArrayList
ArrayListName.clear() //empties the ArrayList
ArrayListName.contains(object); // check if object is in the ArrayList
ArrayListName.IndexOf(object); // returns the index of the object
ArrayListName.isEmpty(); // check wether the list is empty
ArrayListName.size(); //dimension of the ArrayList
ArrayListName.tirmToSize(); // reduce ArrayList size to minimum needed
// ArrayList size doubles when a reseize is needed.
// ArrayList size doubles when a resize is needed.
//run through to the collection with functional programming (JAVA 1.8+)
ArrayListName.forEach(item -> function(v));
@ -94,7 +94,7 @@ class ClassName implements Comparable<ClassName> {
List<ClassName> list;
//valorize List
Collections.sort(list); //"natuarl" sorting uses compareTo()
Collections.sort(list); //"natural" sorting uses compareTo()
```
Otherwise a `Comparator()` must be implemented:
@ -116,7 +116,7 @@ Comparator<ClassName> comparator = new Comparator<ClassName>() {
List<ClassName> list;
//valorize List
Collections.sort(list, comparator); //"natuarl" sorting uses compareTo()
Collections.sort(list, comparator); //"natural" sorting uses compareTo()
```
`Comparator<T>` and `Conmparable<T>` are functional interfaces
`Comparator<T>` and `Comparable<T>` are functional interfaces

115
Java/Java Web/JSP.md
View file

@ -1,115 +0,0 @@
# Java Server Pages Cheat Sheet
Java embedded in html.
Codice + JSP salvati in file `.war`
[TEMP Notes Source](https://github.com/maboglia/CorsoJava/blob/master/appunti/057_JSP_appunti.md#corso-jsp---le-direttive)
## Directives
Le direttive Le direttive permettono di definire la struttura di tutto il documento JSP. Indicano gli aspetti principali del *servlet* in cui sarà convertito il file JSP.
Sono processati al momento della conversione in servlet, a compile-time.
Le direttive esistenti sono: *page*, *include* e *taglib*.
- `<%@ page attribute="value" %>`
- `<%@ include file="path" %>`
- `<%@ taglib ...%>`
Introdotte dal simbolo `@` possono contenere diversi attributi, in alcuni casi concatenabili come per la direttiva import.
### Attributi Direttiva `Page`
**`import="package.class"`**
Lista di package o classes, separati da virgola, che saranno importati per essere utilizzati nel codice java.
**`session ="true | false"`**
Specifica se la pagina fa parte di una sessione HTTP. Se si inizializza a true, è disponibile l'oggetto implicito sessione.
**`buffer ="dimensione-kb"`**
Specifica la dimensione di un buffer di uscita di tipo stream, per il client.
**`errorPage="url"`**
Specifica una pagina JSP che sarà processata nel caso si verifichi un errore.
**`isErrorPage="true|false"`**
Indica che la pagina è una pagina di errore JSP e può mostrare a video l'output dell'errore verificatosi. Per default è settata false.
**`contentType="MIME-Type"`**, **`contentType="MIME-Type; charset=Character-Set"`**
valore MIME di default è text/html
### Direttiva `Include`
Indica al motore JSP di includere il contenuto del file corrispondente, inserendolo al posto della direttiva nella pagina JSP. Il contenuto del file incluso è analizzato al momento della traduzione del file JSP e si include una copia del file stesso nel servlet generato. Una volta incluso, se si modifica il file non sarà ricompilato nel servlet. Il tipo di file da includere può essere un file html (*statico*) o un file jsp (*dinamico*).
```jsp
<html>
<head>
<title> pagina di prova Direttive </title>
</head>
<body>
<h1>pagina di prova Direttive inclusione</h1>
<%@ include file="/hello_world.html" %>
<%@ include file=”/login.jsp” %>
</body>
</html>
```
### Direttiva `Taglib`
Permette estendere i marcatori di JSP con etichette o marcatori generati dall'utente (etichette personalizzate).
Sintassi: `<%@ taglib uri="taglibraryURI" prefix="tagPrefix" %>`
Esempi librerie standard:
- JSTL core
- JSTL sql
- JSTL function
## Implicit Objects
JSP utilizza gli oggetti impliciti (built-in).
Gli oggetti impliciti sono oggetti istanziati automaticamente dall’ambiente JSP, non dobbiamo preoccuparci di importarli e istanziarli.
Per utilizzarli è sufficiente usare la sintassi `nomeOggetto.nomeMetodo`.
Oggetti disponibili per l’uso in pagine JSP:
- **out**: per scrivere codice HTML nella risposta (System.out di Java)
- **session**: dati specifici della sessione utente corrente
- **request**: richiesta HTTP ricevuta e i suoi attributi, header, cookie, parametri, etc.
- **page**: la pagina e le sue proprietà.
- **config**: dati di configurazione
- **response**: risposta HTTP e le sue proprietà.
- **application**: dati condivisi da tutte le pagine della web application
- **exception**: eventuali eccezioni lanciate dal server; utile per pagine di errore
- **pageContext**: dati di contesto per l’esecuzione della pagina
Gli oggetti impliciti possono essere:
- oggetti legati alla servlet relativa alla pagina JSP
- oggetti legati all’input e all’output della pagina JSP
- oggetti che forniscono informazioni sul contesto in cui la JSP viene eseguita
- oggetti risultanti da eventuali errori
Ambito Definisce dove e per quanto tempo saranno accessibili gli oggetti (oggetti impliciti, JavaBeans, ...):
- di pagina: l'oggetto è accessibile dal servlet che rappresenta la pagina
- di richiesta: l'oggetto viene creato e poi distrutto dopo l'uso
- di sessione: l'oggetto è accessibile durante tutta la sessione
- di applicazione: l'oggetto è accessibile dal servlet che rappresenta la pagina
---
## Code in JSP Page
`<% /* code here */ %>` is used to embed java code in a JSP page.
`<%= var %>` is used to get a value from a variable to be displayed.
### Request Parameters
```java
Type variable = request.getParameter("request_parameter"); // parameter of a GET request
```

2
Java/Java Web/Servlet.md
View file

@ -32,7 +32,7 @@ public class <className> extends HttpServlet {
// POST REQUEST: add stuff to DB, page, ...
doGet(request, response); // return same page with new conted added (default case)
doGet(request, response); // return same page with new content added (default case)
}
}
```

154
Java/Java.md
View file

@ -25,7 +25,7 @@ public static void main (String[] args) {
}
```
### Variable Assignement
### Variable Assignment
`Type variable_1 = <expr>, ..., variable_n = <expr>;`
@ -59,7 +59,7 @@ System.out.printf("string %..", variable);
System.out.println(String.format(format, args));
```
Methods ereditated from C. The value pf the variable substitutes %.
Methods inherited from C. The value pf the variable substitutes %.
`%d` int, `%f` float, `%c` char, `%s` string, `%e` scientific notation.
`%digitNumber.decimalDigitNumber` specifies the space occupied by the output.
@ -81,9 +81,9 @@ scanner.close() //closing of Scanner, releases memory
int variable_int_1 = scanner.nextInt(); //takes integer number
String string_1 = scanner.nextLine(); //takes line of text (\n ends line)
String string_1 = scanner.next(); //takes text (spacec ends word)
String string_1 = scanner.next(); //takes text (space ends word)
double variable_double_1 = scanner.nextDouble(); //takes double decimal number
boolean variable_bool = scanner.netxBoolean(); //takes boolean value
boolean variable_bool = scanner.nextBoolean(); //takes boolean value
//(TRUE, FALSE, true, false, True, False)
```
@ -110,7 +110,7 @@ If not specified int & double are the default types.
### Floating-Point numbers & Precision Calcs
Don't use `==` or `!=` to confront floating value numbers since they use approximation or have a lot of digits.
It's best to check if the difference between two numbers is small enought.
It's best to check if the difference between two numbers is small enough.
For high precision calcs is best to use `BigDecimal`.
### Type Conversion (casting) & Type checking
@ -126,7 +126,7 @@ Every primitive type has a corresponding wrapper class.
Wrapper classes permits the creation of an object with the same type of a primitive type but with added methods and constants.
```java
WrapperClass objectName = new WrapperClass(primitiveValue); //decalration
WrapperClass objectName = new WrapperClass(primitiveValue); //declaration
WrapperClass objectName = primitiveValue; //shortened declaration
@ -182,19 +182,19 @@ int i = integer.parseInt(string);
```java
string.equals(otherString); // returns TRUE if the strings are equal
srting.equalsIgnoreCase(otherString); // returns TRUE if the strings are equals ignoring the case
string.charAt(index); // returns the character at positon INDEX
string.equalsIgnoreCase(otherString); // returns TRUE if the strings are equals ignoring the case
string.charAt(index); // returns the character at position INDEX
string.startsWith(otherString); // returns TRUE if string starts with otherString
string.endsWith(otherString) // returns TRUE if string ends with otherString
string.concat(otherString); // concatenation of two strings
string.indexOf(otherString); // returns index of the first occurrence of othre string
string.lastIndexOf(otherString); // returns index of the last occurrence of othre string
string.indexOf(otherString); // returns index of the first occurrence of other string
string.lastIndexOf(otherString); // returns index of the last occurrence of other string
string.length(); // returns the length of the string
string.toLowerCase(); // transform the string in uppercase characters
string.toUpperCase(); // transform the string in lowercase characters
string.repalce(character, newCharacter); // substitutes character with newCharacter
string.replaceAll(regex, replacecment);
string.substring(start, end); // returns a substring starting as START and ending at END (incluced)
string.replace(character, newCharacter); // substitutes character with newCharacter
string.replaceAll(regex, replacement);
string.substring(start, end); // returns a substring starting as START and ending at END (included)
string.trim(); // removes spaces before and after the string
string.Split(delimiter); // return a String[] generated by splitting string at the occurrence of delimiter
string.compareTo(otherString);
@ -207,7 +207,7 @@ string.compareTo(otherString);
- `1` if `otherString` precedes `string`
`compareTo()` compares the lexicographic order (based on UNICODE).
To compare in alphabetical order voth strings must have the same case.
To compare in alphabetical order both strings must have the same case.
### Mathematical Operations
@ -280,7 +280,7 @@ a `^` b | bitwise **XOR**
a `<<` b | bitwise left shift
a `>>` b | bitwise right shift
### Compound Assignement Operators
### Compound Assignment Operators
operator | operation
-----------|----------
@ -298,8 +298,8 @@ a `>>=` b | a = a >> b
### Operator Precedence
1. unary operators `++` , `--`, `!`
2. binary arithmetic opeartors `*`, `/`, `%`
3. binary arithmetic opeartors `+`, `-`
2. binary arithmetic operators `*`, `/`, `%`
3. binary arithmetic operators `+`, `-`
4. boolean operators `<`, `>` , `<=`, `>=`
5. boolean operators `==`, `!=`
6. bitwise operator `&`
@ -414,8 +414,8 @@ The iterator declared in the for is a local variable and can be used only in the
### Assertion Checks
If the asertion check is enabled (`java -ebableassetrions programName`) the execution of the algorithm is terminated if an assertion fails.
Asseretions can be used to check if a variable has a wanted value in a precise point in the code (Sanity Check).
If the assertion check is enabled (`java -ebableassetrions programName`) the execution of the algorithm is terminated if an assertion fails.
Assertions can be used to check if a variable has a wanted value in a precise point in the code (Sanity Check).
```java
assert <booleanExpression>;
@ -451,7 +451,7 @@ ClassName.methodName(arguments); //if method is used outside its class
## Array
## Array Delcaration
## Array Declaration
```java
Type[] arrayName = new Type[dimension];
@ -468,10 +468,10 @@ Type[] arrayName;
arrayType = new Type[dimension];
```
## Array Creation by Initializzation
## Array Creation by Initialization
`Type[] arrayName = {value1, value2, ...}`
Array dimansion is determined by the number of values.
Array dimension is determined by the number of values.
### Arrays as method parameters
@ -517,7 +517,7 @@ Type[]...[] arrayName = new Type[dimension1]...[dimensionN];
Type arrayName[]...[] = new Type[dimension1]...[dimensionN];
```
### Multi-Dimensional Arrats as parameters
### Multi-Dimensional Arrays as parameters
```java
static Type methodName (Type[]...[] ArrayName) {
@ -538,7 +538,7 @@ static Type[]...[] methodName (parameters) {
### Array Length of multi-dimensional arrays
```java
array.length //row lenght
array.length //row length
array[rowIndex].length //column length
```
@ -557,15 +557,15 @@ static void viewTable (Type[][] matrix){
## Recursion Guidelines
The core of the recursion must be constituited by a *conditional instruction* that permits to handle the cases basend on the method argument.
*At laest one* of the alternatives must contain a recurive call to che mathod. The call must resolve recuced version of the task handled by the method.
*At leats one* of the alternatives must not contain a recursive call or it must produce a value that constituites a base case or an arrest value.
The core of the recursion must be constituted by a *conditional instruction* that permits to handle the cases based on the method argument.
*At least one* of the alternatives must contain a recursive call to che method. The call must resolve reduced version of the task handled by the method.
*At leats one* of the alternatives must not contain a recursive call or it must produce a value that constitutes a base case or an arrest value.
## Exception Handling
An **Exception** is an object used to signal an anomalous event.
**Checked Exceptions** must be handled in a catch meanwhile **Uncchecked Exceptions** do not need to be catched like `RuntimeException`.
Unchecked exceptions usually mean thathere is an error in the logic of the program that must be fixed.
**Checked Exceptions** must be handled in a catch meanwhile **Unchecked Exceptions** do not need to be cached like `RuntimeException`.
Unchecked exceptions usually mean that there is an error in the logic of the program that must be fixed.
### `Try-Catch-Finally`
@ -576,7 +576,7 @@ try {
//monitored code
} catch (SpecificException e) {
//in case of errors use this
} catch (SpecificException1 | SpecficException2 | ... | SpecificExceptionN e) {
} catch (SpecificException1 | SpecificException2 | ... | SpecificExceptionN e) {
//in case of errors use this
} catch (Exception e) {
//in case of error use this
@ -594,7 +594,7 @@ A `try-catch` construct can handle multiple exceptions at once. Every `catch` i
try (
//resource definition
){
//dangerious code
//dangerous code
} catch (Exception e) {
//in case of error use this
} finally {
@ -619,7 +619,7 @@ The `throws` keyword is used to indicate what exception Type may be thrown by a
`throws` is used together with a exception class. It's used to send the exception to the method caller.
```java
Type methodName(parameters) throws ExcpetionClass {
Type methodName(parameters) throws ExceptionClass {
if (condition) {
throw new SpecificException("error message");
}
@ -651,7 +651,7 @@ public class CustomException extends Exception {
### Access Modifiers
`public` variables, methoda, classes are usable outside of class of definition.
`public` variables, methods, classes are usable outside of class of definition.
`private` variables, methods, classes are *only* usable inside class of definition.
`protected` variables, methods, classes can be accessed *only* by defining class, it's descendants and the package.
`final` classes and methods cannot be extended or overridden.
@ -701,28 +701,28 @@ It's possible to use `this` to distinguish between instance and static variables
### Classes and Reference Addresses
A an instance of a class doesen't contain an object of that class but a memory address in whitch the object is memorized.
operations of assignement (`=`) and confront (`==`) act on the memory address and not on the values of the objects.
To confront object is necessary to define a `equals()` method that chacks if the values of the object attributes are equal.
A an instance of a class doesn't contain an object of that class but a memory address in which the object is memorized.
operations of assignment (`=`) and confront (`==`) act on the memory address and not on the values of the objects.
To confront object is necessary to define a `equals()` method that checks if the values of the object attributes are equal.
### Constructors
Constructrs are special methods that are invoked with the `new` operator when an object is instantiated.
Constructors are special methods that are invoked with the `new` operator when an object is instantiated.
Constructors assign the starting values of the object attributes.
If a constructor id defined Java doesen't create the default constructor.
If a constructor id defined Java doesn't create the default constructor.
```java
class ClassName (){
//attributes dclaration (aka instance variables)
//attributes declaration (aka instance variables)
//constuctor
//constructor
public ClassName(parameters){
this.attribute = value; //value is passed to the constructor at obj instantiation
}
public ClassName(parameters, otherParameters){
this(parameters); // invoke other consstructor for subset of parameters, must be FIRST INSTRUCTION
this(parameters); // invoke other constructor for subset of parameters, must be FIRST INSTRUCTION
this.attribute = value; // deal with the remaining parameters
}
}
@ -731,7 +731,7 @@ class ClassName (){
### Static Variables
`Type staticVariable = value;`
Statc variables are shared by all objects of a class and all static method can act upon them.
Static variables are shared by all objects of a class and all static method can act upon them.
Static variable do not belong to the class objects.
### Getters & Setter Methods
@ -760,7 +760,7 @@ Public String toString(){
### Static Methods in Classes
Static methods are used to effectuate operations not applied to objects.
Outside of the class of definition thay are invoked with ClassName.methodName()
Outside of the class of definition that are invoked with ClassName.methodName()
Static method **cannot** act on instance variables.
### Method Overloading
@ -778,14 +778,14 @@ Child class **must** implement a constructor that instantiates the parent (super
`super()` instantiates the superclass of the child class.
```java
class ChildClass extends PerentClass{
class ChildClass extends ParentClass{
public ChildClass(parentParameters, childParameters){
super(parentParameters); // if omitted super() is calles (parent's default constructor)
// assignement of child attributes
super(parentParameters); // if omitted super() is calls (parent's default constructor)
// assignments of child attributes
}
//calss overrides parent class (must have same name)
//calls overrides parent class (must have same name)
@Override
Type methodName(parameters){
//code here
@ -795,7 +795,7 @@ class ChildClass extends PerentClass{
}
```
An overridden method that returns a `ParentClass` can be overridden to return a `ChildClass`. This is the only case in which an overridden method can change the retured type.
An overridden method that returns a `ParentClass` can be overridden to return a `ChildClass`. This is the only case in which an overridden method can change the returned type.
An overridden method can change the access modifier as long as the new modifier is more "permissive".
A `ParentClass` type can contain a `ChildClass` object. This is useful for using collections and arrays of objects.
@ -805,17 +805,17 @@ ParentClass objectName = ChildClass(); // upcast
(ChildClass)ParentClassObject; // downcast
```
### Abstact Classes & Abstract Methods
### Abstract Classes & Abstract Methods
An Abstact Class is a particular class that contains an Abstact Method.
This type of class cannot be instantiated but is used leave the specific implementatio of some of it's methods to extending classes.
Abstact classes are marked by the `abstract` keyword.
An Abstract Class is a particular class that contains an Abstract Method.
This type of class cannot be instantiated but is used leave the specific implementation of some of it's methods to extending classes.
Abstract classes are marked by the `abstract` keyword.
An abstract method is a method witout imlementation.
An abstract method is a method without implementation.
The methods **must** be `public` and marked with the `abstract` keyword.
```java
//abstarct class
//abstract class
abstract class className{
//attributes here
//constructor here
@ -828,12 +828,12 @@ abstract class className{
### Interfaces
An Interface is a class with *only* abstact methods. An interface has more flexibility than an abstract class.
Interfaces are used to set requirements for child clases without specifing how to satisfy those requirements since it's methods will be implemented in child classes.
An Interface is a class with *only* abstract methods. An interface has more flexibility than an abstract class.
Interfaces are used to set requirements for child classes without specifying how to satisfy those requirements since it's methods will be implemented in child classes.
An Interface is marked by the `interface` keyword.
If an implementing class implements only `some` of the interface's mathod than the class **must be abstract**.
If an implementing class implements only `some` of the interface's method than the class **must be abstract**.
Interfaces' methods are always `abstract` and `public`, no need for the kyword.
Interfaces' methods are always `abstract` and `public`, no need for the keyword.
Interfaces' attributes are always `public static final`, no need for the keyword.
A class can implement *more than one* Interface.
@ -849,7 +849,7 @@ public interface InterfaceName{
public interface OtherInterface extends InterfaceName {
//attributes here
Type methodName(); // inherited from extended interface
Type otherMethod(); // defined in thes interface
Type otherMethod(); // defined in the interface
}
class ClassName implements Interface1, Interface2 {...}
@ -858,16 +858,16 @@ class ClassName implements Interface1, Interface2 {...}
Types of Interfaces:
- Normal (multiple methods)
- Single Abstract Method (`@FunctionalInterface`, used with *Lamda Expressions*)
- Single Abstract Method (`@FunctionalInterface`, used with *Lambda Expressions*)
- Marker (Empty, *no methods*)
Since Java 1.8 interfaces can implements also `static` methods.
### Enumerations
Enums are used to restrict the type of data to a set of the possible constatnt values.
Enums are used to restrict the type of data to a set of the possible constant values.
Enums are classes which constructor is private by default.
It's still possible to createa a custom constructor to add values.
It's still possible to create a custom constructor to add values.
```java
enum enumName {
@ -887,13 +887,13 @@ enum enumName {
private Type value;
Type enumName(Type paramenter) {
Type enumName(Type parameter) {
this.value = parameter;
}
//getters are allowed, the values is a constant --> no setters
public Type getValue(){
retrurn this.value;
return this.value;
}
}
@ -916,7 +916,7 @@ AnonymousClass objectName = new AnonymousClass(Type parameter, ...) {
### Cloning
```java
class ClassName implements Cloneable {
class ClassName implements Clonable {
}
```
@ -1012,13 +1012,13 @@ try{
}
// write on the file
outSteram.print("");
outSteram.println("");
outStream.print("");
outStream.println("");
outStream.close() // close stream and write buffer contents.
```
**Note**: writing operations do not write direcly on the file. The sent data is collected in a **buffer**. When the buffer is *full* the data is written in the file. This is called *buffering* and is used to spped up operations.
**Note**: writing operations do not write directly on the file. The sent data is collected in a **buffer**. When the buffer is *full* the data is written in the file. This is called *buffering* and is used to append up operations.
#### Reading from a file
@ -1047,31 +1047,31 @@ try {
// code here
}
// BuffredReader Methods
// BufferedReader Methods
public String readLine() throws IOException // return file line or null (file has ended)
public int read() throws IOException // return an integer representin a char or -1 (file has ended)
public int read() throws IOException // return an integer representing a char or -1 (file has ended)
public long skip(n) throws IOException // skip n characters
public void close() throws IOException // closes the stream
```
#### `File()` class
The File class is an abstraction of the file and it's path. The abstraction is independant from the OS.
The File class is an abstraction of the file and it's path. The abstraction is independent from the OS.
```java
File("path/to/file") // UNIX like path
File("path\\to\\file") // Windows path
file.canRead() // true if file is readeble
file.canRead() // true if file is readable
file.canWrite() // true if file is writable
file.delete() // true if file has been deleted
file.exists() // check if exist a file with the filename used in the constructor
file.getName() // returns the filename
file.getPath() // returns the file's path
file.lenghth() // file lenght in bytes
file.length() // file length in bytes
```
### Bynary Files
### Binary Files
#### Writing to a binary file
@ -1146,7 +1146,7 @@ Needed for a class to be *serializable*:
- all instance variables are serializable
- superclass, if exists, is serializable or has default constructor
An array is serializable if it's base type is a rerializable object.
An array is serializable if it's base type is a serializable object.
```java
SerializableObject[] array = (SerializableObject[])inStream.readObject(); // read returns Object, cast needed
@ -1158,7 +1158,7 @@ SerializableObject[] array = (SerializableObject[])inStream.readObject(); // re
Functional interfaces provide target types for *lambda expressions*.
General purpose `@functioanlInterfaces`:
General purpose `@functionalInterfaces`:
```java
// takes input, performs actions, return boolean
@ -1189,7 +1189,7 @@ In java a *stream* is a [Monad][1]. Monads allow the programmer to compose a seq
The features of Java stream are:
- A stream is not a data structure instead it takes input from the Collections, Arrays or I/O channels.
- Streams don’t change the original data structure, they only provide the result as per the pipelined methods.
- Streams don't change the original data structure, they only provide the result as per the pipelined methods.
- Each intermediate operation is lazily executed and returns a stream as a result, hence various intermediate operations can be pipelined. Terminal operations mark the end of the stream and return the result.
**Intermediate Operations**:

8
Java/Spring Framework/Spring Project Structure.md
View file

@ -25,7 +25,7 @@ server.port=server_port
Model of a table of the DB
```java
package <base_pakcage>.entities;
package <base_package>.entities;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
@ -106,7 +106,7 @@ public interface IEntityService {
In `EntityService.java`:
```java
package com.lamonacamarcello.libri.services;
package <base_package>.services;
import java.util.List;
@ -162,7 +162,7 @@ public class EntityService implements IEntityService {
REST API routes & endpoints to supply data as JSON.
```java
package com.lamonacamarcello.libri.integration;
package <base_package>.integration;
import java.util.List;
@ -178,7 +178,7 @@ import <base_package>.services.IEntityService;
@RequestMapping("/api") // controller route
public class EntityRestCtrl {
@Autowired // connection to service (obj created by spring as needed: Inverion Of Control)
@Autowired // connection to service (obj created by spring as needed: Inversion Of Control)
private IEntityService service;
@GetMapping("entities") // site route

6
JavaScript/AJAX.md
View file

@ -20,8 +20,8 @@ var request = new XMLHttpRequest();
request.addEventListener(event, function() {...});
request.open("HttpMethod", "path/to/api", true); // third parameter is asynchronicity (true = asynchronous)
reqest.setRequestHeader(key, value) // HTTP Request Headers
reqest.send()
request.setRequestHeader(key, value) // HTTP Request Headers
request.send()
```
To check the status use `XMLHttpRequest.status` and `XMLHttpRequest.statusText`.
@ -75,7 +75,7 @@ request.send();
### `XMLHttpRequest` Browser compatibility
Old versions of IE don’t implement XMLHttpRequest. You must use the ActiveXObject if XMLHttpRequest is not available
Old versions of IE don't implement XMLHttpRequest. You must use the ActiveXObject if XMLHttpRequest is not available
```js
var request =window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP');

12
JavaScript/DOM.md
View file

@ -26,7 +26,7 @@ var node = document.querySelector('css-selector');
var nodes = document.querySelectorAll('css-selector');
```
## Manupulating the DOM
## Manipulating the DOM
### Manipulating a node's attributes
@ -43,7 +43,7 @@ var node = document.getElementById('id');
node.className = 'new-class';
```
### Manipulating a node’s style
### Manipulating a node's style
It's possible to access and change the styles of a DOM nodes via the **style** property.
CSS property names with a `-` must be **camelCased** and number properties must have a unit.
@ -63,7 +63,7 @@ pageNode.style.backgroundColor = 'pink';
pageNode.style.paddingTop = '10px';
```
### Manipulating a node’s contents
### Manipulating a node's contents
Each DOM node has an `innerHTML` attribute. It contains the HTML of all its children.
@ -103,7 +103,7 @@ In `page.html`:
In `script.js`:
```js
var formNode = document.getEleementById("Identifier");
var formNode = document.getElementById("Identifier");
var value = formNode.value;
```
@ -123,7 +123,7 @@ domNode.insertBefore(childToInsert, domnode);
domNode.parentNode.insertBefore(childToInsert, nodeAfterChild);
// remove a node
domnNod.removeChild(childToRemove);
domNode.removeChild(childToRemove);
node.parentNode.removeChild(node);
```
@ -152,7 +152,7 @@ body.appendChild(newParagraph);
function Node(params) {
this.node = document.createElement("tag");
this.node.attrubute = value;
this.node.attribute = value;
// operations on the node

6
JavaScript/Events & Animation.md
View file

@ -20,8 +20,8 @@ var onEvent = function(event) { // parameter contains info on the triggered eve
// logic here
}
domNode.addEventListener(eventType, calledback);
domNode.renoveEventListener(eventType, callback);
domNode.addEventListener(eventType, callback);
domNode.removeEventListener(eventType, callback);
```
### Bubbling & Capturing
@ -44,7 +44,7 @@ let event = new CustomEvent(type, { detail: /* custom data */ }); // create eve
domNode.dispatchEvent(event); // launch the event
```
![Event Inheritace](../.images/javascript_event-inheritance.png)
![Event Inheritance](../.images/javascript_event-inheritance.png)
## Animation

86
JavaScript/JavaScript.md
View file

@ -24,7 +24,7 @@
* @author author's name
* purpose of file
*
* detailed explanantion of what the file does on multiple lines
* detailed explanation of what the file does on multiple lines
*/
```
@ -56,7 +56,7 @@ alert("message");
[var vs let vs const](https://www.freecodecamp.org/news/var-let-and-const-whats-the-difference/)
Variable names can only contain numbers, digits, underscores and $. Varieble names are camelCase.
Variable names can only contain numbers, digits, underscores and $. Variable names are camelCase.
`let`: Block-scoped; access to variable restricted to the nearest enclosing block.
`var`: Function-scoped
@ -66,8 +66,8 @@ Variable names can only contain numbers, digits, underscores and $. Varieble nam
### Scope
Variabled declared with `let` are in local to the code block in which are declared.
Variabled declared with `var` are local only if declared in a function.
Variable declared with `let` are in local to the code block in which are declared.
Variable declared with `var` are local only if declared in a function.
```js
function func(){
@ -121,9 +121,9 @@ let string$ = 'text';
let string_ = `text ${expression}`; //string interpolation (needs backticks)
string.length; // length of the string
let char = string.charAt(index); // extaraction of a single character by position
let char = string.charAt(index); // extraction of a single character by position
string[index]; // char extraction by property access
let index = strinf.indexOf(substring); // start index of substring in string
let index = string.indexOf(substring); // start index of substring in string
```
Property access is unpredictable:
@ -170,7 +170,7 @@ typeof x; //returns the type of the variable x as a string
typeof(x); //returns the type of the variable x as a string
```
The result of typeof null is "object". That’s wrong.
The result of typeof null is "object". That's wrong.
It is an officially recognized error in typeof, kept for compatibility. Of course, null is not an object.
It is a special value with a separate type of its own. So, again, this is an error in the language.
@ -179,12 +179,12 @@ It is a special value with a separate type of its own. So, again, this is an err
```javascript
String(value); //converts value to string
Number(value); //converst value to a number
Number(value); //converts value to a number
Number(undefined); //--> NaN
Number(null); //--> 0
Number(true); //--> 1
Number(false); //--> 0
Number(String); //Whitespaces from the start and end are removed. If the remaining string is empty, the result is 0. Otherwise, the number is “read” from the string. An error gives NaN.
Number(String); //Whitespace from the start and end is removed. If the remaining string is empty, the result is 0. Otherwise, the number is "read" from the string. An error gives NaN.
Boolean(value); //--> true
Boolean(0); //--> false
@ -211,8 +211,8 @@ Number("A") == NaN; //false ?!?
```js
2 + 'text'; //"2text", implicit conversion and concatenation
1 + "1"; //"11", implicit conversion and concatention
"1" + 1; //"11", implicit conversion and concatention
1 + "1"; //"11", implicit conversion and concatenation
"1" + 1; //"11", implicit conversion and concatenation
+"1"; //1, implicit conversion
+"text"; // NaN
1 == "1"; //true
@ -231,7 +231,7 @@ Number("A") == NaN; //false ?!?
| `new` a(...) | object creation |
| a `in` b | membership |
### Mathemetical Operators
### Mathematical Operators
| Operator | Operation |
| -------- | -------------- |
@ -247,9 +247,9 @@ Number("A") == NaN; //false ?!?
| Operator | Operation |
| ------------ | ----------------- |
| `--`variable | prefix decrement |
| `++`variable | prefix incremente |
| variable`--` | postfiz decrement |
| variable`++` | ostfix increment |
| `++`variable | prefix increment |
| variable`--` | postfix decrement |
| variable`++` | postfix increment |
### Logical Operators
@ -267,7 +267,7 @@ Number("A") == NaN; //false ?!?
| a `<=` b | less or equal to |
| a `>` b | greater than |
| a `>=` b | greater or equal to |
| a `==` b | equaltity |
| a `==` b | equality |
| a `!=` b | inequality |
| a `===` b | strict equality |
| a `!==` b | strict inequality |
@ -281,8 +281,8 @@ Number("A") == NaN; //false ?!?
| a `^` b | bitwise XOR |
| `~`a | bitwise NOT |
| a `<<` b | bitwise left shift |
| a `>>` b | bitwise rigth sigt |
| a `>>>` b | bitwise unsigned rigth shift |
| a `>>` b | bitwise right shift |
| a `>>>` b | bitwise unsigned right shift |
### Compound Operators
@ -364,19 +364,19 @@ do {
### For Loop
```javascript
// baseic for
// basic for
for (begin; condition; step) { }
for (var variable in iterable) { } // for/in statement loops through the properties of an object
for (let variable in iterable) { } // inistatiate a new variable at each iteration
for (let variable in iterable) { } // instantiate a new variable at each iteration
// for/of statement loops through the values of an iterable objects
// for/of lets you loop over data structures that are iterable such as Arrays, Strings, Maps, NodeLists, and more.
for (var variable of iterable) { }
for (let variable of iterable) { } // inistatiate a new variable at each iteration
for (let variable of iterable) { } // instantiate a new variable at each iteration
// foreach (similar to for..of)
itearble.forEach(() => { /* statements */ });
iterable.forEach(() => { /* statements */ });
```
### Break & Continue statements
@ -385,11 +385,11 @@ itearble.forEach(() => { /* statements */ });
`continue;` skip to next loop cycle.
```javascript
labelname: for(begin; condition; step) {
label: for(begin; condition; step) {
//code here
}
break labelname; //breaks labelled loop and nested loops inside it
break label; //breaks labelled loop and nested loops inside it
```
## Arrays
@ -405,9 +405,9 @@ array[index] = item; // change or add item by index
array.push(item); //add item to array
array.pop(); // remove and return last item
array.join("separator"); // constuct a string from the items of the array, sepatated by SEPARATOR
array.join("separator"); // construct a string from the items of the array, separated by SEPARATOR
array.find(item => condition); // returns the value of the first element in the provided array that satisfies the provided testing function
array.fill(value, start, end); // filla an array with the passed value
array.fill(value, start, end); // fills an array with the passed value
// https://stackoverflow.com/a/37601776
@ -438,7 +438,7 @@ let array1 = [ 1, 2, 3, 4, 5, 6 ];
let array2 = [ 7, 8, 9, 10 ];
let copy = [ ...array1 ]; // shallow copy
let copyAndAdd = [ 0, ...array1, 7 ]; // insert all values in new array
let merge = [ ...array1, ...attay2 ]; // merge the arrays contents in new array
let merge = [ ...array1, ...array2 ]; // merge the arrays contents in new array
// objects
let obj = { prop1: value1, prop2: value2 };
@ -507,7 +507,7 @@ function functionName(parameter=default-value, ...args) {
```javascript
function functionName(parameters) {
if (parameter == undefined) {
paremeter = value;
parameter = value;
}
//code here
@ -542,7 +542,7 @@ let func = input => expression;
func(); // function call
// rerurn object literal
// return object literal
let func = (value) => ({property: value});
```
@ -550,7 +550,7 @@ let func = (value) => ({property: value});
An object is a collection of related data and/or functionality.
**Note**: It's not possible to transform a variable in an object simply by using the object assignement.
**Note**: It's not possible to transform a variable in an object simply by using the object assignment.
```js
let variable = value;
@ -567,7 +567,7 @@ let obj = {
method: function() {
// code here
this.properyName; // reference to object property inside the object
this.propertyName; // reference to object property inside the object
}
method; () => {
@ -575,7 +575,7 @@ let obj = {
}
};
// access to property (non existant porperties will return Undefined)
// access to property (non existant properties will return Undefined)
obj.property; // dot notation
obj["property"]; // array notation
@ -601,12 +601,12 @@ Notice that it has all the features you'd expect in a function, although it does
function Class(params) {
this.property = param;
this.method = function(parms) { /* code here */ }
this.method = function(params) { /* code here */ }
}
let obj = new Class(params); // object instantiation
let obj = new Object(); // cretaes empty object
let obj = new Object(); // creates empty object
let obj = new Object({
// JSON
});
@ -623,7 +623,7 @@ This is often referred to as a **prototype chain**, and explains why different o
If a method is implemented on an object (and not it's prototype) then only that object will heve that method and not all the ones that come from the same prototype.
```js
// constuctor function
// constructor function
function Obj(param1, ...) {
this.param1 = param1,
...
@ -712,10 +712,10 @@ let obj = {
let { var1, var2 } = obj; // extract values from object into variables
let { property: var1, property2 : var2 } = obj; // extract props in variables w/ specified names
let { property: var1, var2 = defalut_value } = obj; // use default values if object has less then expected props
let { property: var1, var2 = default_value } = obj; // use default values if object has less then expected props
```
### Array Deconstrions
### Array Deconstruction
```js
let array = [ 1, 2, 3, 4, 5, 6 ];
@ -726,10 +726,10 @@ let [first, , third, , seventh = "missing" ] = array; // extract specific value
```js
let object = {
// ojectt attributes
// object attributes
}
let json = JSON.stringify(object); // serialieze onbect in JSON
let json = JSON.stringify(object); // serialize object in JSON
let json = { /* JSON */ };
let object = JSON.parse(json); // deserialize to Object
@ -757,7 +757,7 @@ let timerId = setTimeout(function(arg1, ...){
clearTimeout(timerId) // cancel execution
// exemple of multiple consecutive schedules
// example of multiple consecutive schedules
let list = [1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", -1, -2, -3, -4, -5, -6, -7, -8, -9, -10]
function useTimeout(pos=0) {
@ -766,7 +766,7 @@ function useTimeout(pos=0) {
pos += 1; // update value for next call
if (pos < list.length) { // recursion exit condition
useTimeout(pos); // schedule next call with new walue
useTimeout(pos); // schedule next call with new value
}
}, 1_000, pos);
}
@ -777,7 +777,7 @@ useTimeout();
### `let` vs `var` with `setTimeout`
```js
// let instantitates a new variable for each iteration
// let instantiates a new variable for each iteration
for (let i = 0; i < 3; ++i) {
setTimeout(function() {
console.log(i);
@ -923,7 +923,7 @@ In `page.html`
In `module.js`:
```js
// exporting indivisual fratures
// exporting individual fractures
export default function() {} // one per module
export func = () => expression; // zero or more per module

10
JavaScript/React/React Router.md
View file

@ -1,10 +1,10 @@
# React Router
Popular routing library. Allows to specify a route through React components, declating which component is to be loaded for a given URL.
Popular routing library. Allows to specify a route through React components, declaring which component is to be loaded for a given URL.
Key Components:
- **Router**: wrap the app entrypoint, usually `BrowserRouter`
- **Router**: wrap the app entry-point, usually `BrowserRouter`
- **Route**: "Load this component for this URL"
- **Link**: react-managed anchors that won't post back to the browser
@ -74,7 +74,7 @@ import { Redirect } from "react-router-dom";
<Redirect from="/old-route" to="/new-route" />
{ condition && <Redirect to="/route" /> } // redirect if condition is true
// or redirect manipolating the history (always in props)
// or redirect manipulating the history (always in props)
props.history.push("/new-route");
```
@ -83,13 +83,13 @@ props.history.push("/new-route");
```js
import { Prompt } from "react-router-dom";
// displayes a prompt when the condition is true
// displays a prompt when the condition is true
<Prompt when={condition} message="prompt message" />
```
## Link
Clicks on a link created with React-Router will be captured by ract an all the routing will happen client side.
Clicks on a link created with React-Router will be captured by react an all the routing will happen client side.
```js
import { Link } from "react-router-dom";

12
JavaScript/React/React Tests.md
View file

@ -13,7 +13,7 @@ In `package.json`:
"test": "jest --watch" // watch re-runs test on save
},
"jest": {
// calls additional setups for enzyme, react tesing library, ...
// calls additional setups for enzyme, react testing library, ...
"setupFiles": [
"path/to/testSetup.js"
],
@ -64,16 +64,16 @@ In `Component.Snapshots.js`:
```js
import React from "react";
import rederer from "react-test-renderer";
import renderer from "react-test-renderer";
import Component from "./path/to/Component";
// import mock data if necessary
it("test descrtiption", () => {
it("test description", () => {
// renders the DOM tree of the component
const tree = renderer.create(<Component funcProp={jest.fn() /* mock function */} /* component props */ />);
// save a snaphot of the component at this point in time ( in __snaphsots__ folder)
// save a snapshot of the component at this point in time ( in __snapshots__ folder)
// in future test it will be checked to avoid regressions
// can be updated during jest --watch pressing "u"
expect(tree).matchSnapshot();
@ -89,7 +89,7 @@ it("test descrtiption", () => {
```js
// testSetup.js
import { configure } from "enzyme";
import Adapter from "enzyme-adapert-react-<version>";
import Adapter from "enzyme-adapter-react-<version>";
configure({ adapter: new Adapter() });
```
@ -128,7 +128,7 @@ it("test description", () => {
});
// mount rendering test
if("test descriotion" () => {
if("test description" () => {
const dom = mount(
<WrapperComponent>
<Component /* props *//>

16
JavaScript/React/React.md
View file

@ -2,7 +2,7 @@
## Components
Thera are two types of react components:
There are two types of react components:
- Function Components
- Class Components
@ -29,7 +29,7 @@ class Component extends React.Component {
Every components has two inputs: *props* and *state*. The props input is explicit while the state is implicit. State is used to determine the chages. Within the component state can be changed while the props object represent fixed values.
JSX syntax can resable HTML bat gets converted to pure JavaScript before being sent to the browser:
JSX syntax can reusable HTML bat gets converted to pure JavaScript before being sent to the browser:
```js
// JSX
@ -45,7 +45,7 @@ const element = React.createElement(
);
```
### App Entrypoint
### App Entry-point
```js
ReactDOM.render(
@ -60,7 +60,7 @@ ReactDOM.render(
### Dynamic Expressions
```js
<tag>{expression}</tag> // expression is evalueted an it's result is displayed
<tag>{expression}</tag> // expression is evaluated an it's result is displayed
<tag onEvent={funcReference}>{expression}</tag>
<tag onEvent={() => func(args)}>{expression}</tag>
```
@ -69,7 +69,7 @@ ReactDOM.render(
```js
<Component propName={value} /> // pass a value the component
<Component propName={funcreference} /> // pass a function to the component
<Component propName={funcReference} /> // pass a function to the component
function Component(props) {
// use props with {props.propName}
@ -135,7 +135,7 @@ class Button extends React.Component {
}
```
### Nesting Compnents
### Nesting Components
```js
import { useState } from "react";
@ -225,7 +225,7 @@ const [state, setState] = useState(default);
### `useEffect`
Hook used to trigger an action on each reder of the component or when one of the watched items changes.
Hook used to trigger an action on each render of the component or when one of the watched items changes.
```js
@ -240,7 +240,7 @@ useEffect(() => {
```js
// hook definitions
const useCutomHook = () => {
const useCustomHook = () => {
// eventual state definitions
// eventual function definitions

12
JavaScript/React/Redux Tests.md
View file

@ -2,10 +2,10 @@
## Tests for Connected Components
Connected components are warpped in a call to `connect`. Way of solving the problem:
Connected components are wrapped in a call to `connect`. Way of solving the problem:
- Wrap component with `<Provider>`. Added benefit: new store dedicated to tests.
- Add named export for unconncted component.
- Add named export for unconnected component.
In `Component.js`:
@ -38,8 +38,8 @@ function testHelper(args) {
it("test description", () => {
const dom = testHelper();
// simulate page interation
dom.find("selctor").simulate("<event>");
// simulate page iteration
dom.find("selector").simulate("<event>");
// find changed component
// test expected behaviour of component
@ -91,7 +91,7 @@ import initialState from "path/to/initialState";
import * as actions from "path/to/actionCreators";
it("test description", () => {
const store = createStore(toorReducer, initialState);
const store = createStore(storeReducer, initialState);
const expectedState = /* state after the update */
@ -126,7 +126,7 @@ import * as actions from "path/to/actionCreators";
describe("Async Actions", () => {
afterEach(() => {
fetchMock.restore(); // init fecth mock for each test
fetchMock.restore(); // init fetch mock for each test
});
it("test description", () => {

16
JavaScript/React/Redux.md
View file

@ -57,7 +57,7 @@ export function configStore(initialState) {
replaceReducer(newReducer); // replace an existing reducer, useful for Hot Reload
store.dispatch(action); // trigger a state change based on an action
store.subscribe(listener);
store.getState(); // retireve current state
store.getState(); // retrieve current state
```
### Reducers
@ -106,7 +106,7 @@ Container Components:
- Subscribe to Redux State
- Dispatch Redux actions
Presentaional Components:
Presentational Components:
- Focus on how things look
- Unaware of Redux
@ -145,23 +145,23 @@ import { increment, decrement, reset } from './actionCreators';
// const Component = ...
// specifies which state is passed to the component (called on satte change)
// specifies which state is passed to the component (called on state change)
const mapStateToProps = (state, ownProps /* optional */) => {
// structure of the props passsed to the component
// structure of the props passed to the component
return { propName: state.property };
};
// specifies the action passed to a component (the key is the name that the prop will have )
const mapDispatchToProps = { actionCreator: actionCreator };
// or
function mapDispathToProps(dispatch) {
function mapDispatchToProps(dispatch) {
return {
// wrap action creators
actionCreator: (args) => dispatch(actionCreator(args))
};
}
// or
function mapDispathToProps(dispatch) {
function mapDispatchToProps(dispatch) {
return {
actionCreator: bindActionCreators(actionCreator, dispatch),
actions: bindActionCreators(allActionCreators, dispatch)
@ -177,7 +177,7 @@ export default connect(mapStateToProps, mapDispatchToProps)(Component);
**Note**: Redux middleware runs *after* and action and *before* it's reducer.
Redux-Thunk allows to retrurn functions instead of objects from action creators.
Redux-Thunk allows to return functions instead of objects from action creators.
A "thunk" is a function that wraps an expression to delay it's evaluation.
In `configStore.js`:
@ -199,7 +199,7 @@ function configStore(initialState) {
```
```js
// usally action on async func success
// usually action on async func success
function actionCreator(arg) {
return { type: TYPE, data: arg };
}

6
JavaScript/Svelte/Svelte.md
View file

@ -10,7 +10,7 @@ node scripts/setupTypeScript.js
npm init vite@latest
```
## App Entrypoint
## App Entry-point
```js
import App from "./App.svelte"; // import the component
@ -74,7 +74,7 @@ export default app;
// markup here
{/each}
{#each array as item (key)} // usse key to determine changes
{#each array as item (key)} // use key to determine changes
// markup here
{/each}
```
@ -139,7 +139,7 @@ For these, Svelte has reactive declarations. They look like this:
```js
let count = 0;
$: double = count * 2; // recaclulatd when count changes
$: double = count * 2; // recalculated when count changes
// or
$: { }
$: <expression>

8
JavaScript/jQuery.md
View file

@ -90,9 +90,9 @@ $('a').css({'color': 'purple'});
### Create, Store, Manipulate and inject
```js
let paragraph = $('<p class="intro">Welcome<p>'); // creat and store element
let paragraph = $('<p class="intro">Welcome<p>'); // create and store element
paragraph.css('propery', 'value'); // manipulate element
paragraph.css('property', 'value'); // manipulate element
$("body").append(paragraph); // inject in DOM
```
@ -148,7 +148,7 @@ In the HTML, add a `<script>` ag that hotlinks to the CDN or source file:
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.17.0/jquery.validate.min.js"><script>
```
In the JavaScript call the jQuery puging on the DOM:
In the JavaScript call the jQuery plugin on the DOM:
```js
$("form").validate();
@ -195,7 +195,7 @@ banner.css('color', 'red')
### DOM Readiness
DOM manipulation and event binding doesn’t work if the `<script>` is in the `<head>`
DOM manipulation and event binding doesn't work if the `<script>` is in the `<head>`
```js
$(document).ready(function() {

10
Kotlin/kotlin.md
View file

@ -1,6 +1,6 @@
# Kotlin Cheat Sheet
## Pakage & Imports
## Package & Imports
```kotlin
package com.app.uniqueID
@ -21,13 +21,13 @@ val CONSTANT_NAME: Type = value //constant declaration
### Nullable Variables
For a variable to hold a null value, it must be of a nullable type.
Nulalble types are specified suffixing `?` to the variable type.
Nullable types are specified suffixing `?` to the variable type.
```kotlin
var nullableVariable: Type? = null
nullableVariable?.method() //correct way to use
//if var is null dont execute method() and return null
//if var is null don't execute method() and return null
nullablevariavle!!.method() //unsafe way
//!! -> ignore that var can be null
@ -81,7 +81,7 @@ when (variable){
//instead of chain of if-else
when {
condition -> value
condirion -> value
condition -> value
else -> value
}
```
@ -158,7 +158,7 @@ fun functionName(parameter: Type, function: (Type) -> Type): Type {
```kotlin
//primary constructor
class ClassName(private var attrivute: Type) {
class ClassName(private var attribute: Type) {
}

6
Markdown.md
View file

@ -10,7 +10,7 @@ Heading 2
---------
# Heading 1
## Headding 2
## Heading 2
### Heading 3
```
@ -20,7 +20,7 @@ Heading 2
*Italic* _Italic_
**Bold** __Bold__
~GitHub's striketrough~
~GitHub's strike-trough~
```
## Links & Images
@ -74,6 +74,6 @@ Heading 2
```markdown
| column label | column label | column label |
|:-------------|:------------:|--------------:|
| left-aligned | centered | right-alinged |
| left-aligned | centered | right-aligned |
| row contents | row contents | row contents |
```

2
Node.js/Node.js.md
View file

@ -1,6 +1,6 @@
# Node.js
Asyncronous JavaScript Engine
Asynchronous JavaScript Engine
## Syllabus

4
Node.js/Standard Packages/events.md
View file

@ -14,12 +14,12 @@ class CustomEmitter extends EventEmitter {} ;
const customEmitterObj = new CustomEmitter();
// add event listener
cusomEmitterObj.on("event", (e) => {
customEmitterObj.on("event", (e) => {
// e contains event object
})
// single-use event listener (execute and remove listener)
cusomEmitterObj.once("event", (e) => {
customEmitterObj.once("event", (e) => {
// e contains event object
})

4
Node.js/Standard Packages/fs.md
View file

@ -1,6 +1,6 @@
# fs (FIle System) Module
Async versions can acces file at the same time which can lead to conflicts in operations, erros can be handled in callback.
Async versions can access file at the same time which can lead to conflicts in operations, errors can be handled in callback.
Sync versions cannot interfere with each other, errors cause exceptions, handle in try-catch.
## Files
@ -71,7 +71,7 @@ fs.rmdirSync(path, recursive=false;
### Reading Directory Contents
```js
// read directrory contents
// read directory contents
fs.readdir(path, (err, files) => {}); // files is string[]
fs.readdir(path, { withFileTypes: true }, (err, files) => {}); // files is Dirent[]
fs.readdirSync(path); // returns string[] of files/directories

6
Node.js/Standard Packages/http(s).md
View file

@ -1,6 +1,6 @@
# HTTP(S) Module
## HTTTP(S) IncomingMessage (request)
## HTTPS(S) IncomingMessage (request)
### Making a request
@ -17,7 +17,7 @@ https.request(
).end();
```
### Reqest Methods & Properties
### Request Methods & Properties
```js
IncomingMessage.headers
@ -26,7 +26,7 @@ IncomingMessage.statusMessage
IncomingMessage.url
```
## HTTTP(S) ServerResponse (response)
## HTTPS(S) ServerResponse (response)
### Response Methods & Properties

2
Node.js/Standard Packages/os.md
View file

@ -16,5 +16,5 @@ os.homedir(); // CUrrent user home directory
os.hostname(); // PC Name
os.cpus(); // Array of CPU info
os.networkInterfaces(); // Array of Network Interfacecs info
os.networkInterfaces(); // Array of Network Interfaces info
```

2
Node.js/Standard Packages/process.md
View file

@ -15,7 +15,7 @@ process.arch // processor architecture
## Functions
```js
process.resourecUsage(); // resource usage for the current process
process.resourceUsage(); // resource usage for the current process
process.memoryUsage(); // memory usage of the Node.js process measured in bytes
process.exit(code); // terminate the process synchronously with an exit status of code
```

6
PHP/Composer & Autoloading.md
View file

@ -13,13 +13,13 @@ function autoloader($class) {
# __DIR__ -> path of calling file
# $class -> className (hopefully same as file)
# if class is in namesapce $class -> Namespace\className (hopefully folders mirror Namespace)
# if class is in namespace $class -> Namespace\className (hopefully folders mirror Namespace)
$class = str_replace("\\", DIRECTORY_SEPARATOR, $class); # avoid linux path separator issues
$fileName = sprintf("%s\\path\\%s.php", __DIR__, $class);
# or
$filename = sprintf("%s\\%s.php", __DIR__, $class); # if class is in namespaace
$filename = sprintf("%s\\%s.php", __DIR__, $class); # if class is in namespace
if (file_exists($fileName)) {
include $fileName;
@ -41,7 +41,7 @@ require "autoload.php";
### Multiple Autoloading
It's possible to resister multiple autoloading functions by calling `spl_autoloaad_register()` multiple times.
It's possible to resister multiple autoloading functions by calling `spl_autoload_register()` multiple times.
```php
# prepend adds the function at the start of the queue

14
PHP/Database.md
View file

@ -23,7 +23,7 @@ try {
### Queries
To execute a query it's necessaty to "prepare it" with *parameters*.
To execute a query it's necessary to "prepare it" with *parameters*.
```php
# literal string with markers
@ -34,9 +34,9 @@ WHERE field <operator> :marker'
$stmt = $pdo->prepare($sql, $options_array); # returns PDOStatement, used to execute the query
$stmt->execute([ ':marker' => value ]); # substitute marker with actual value
# fetchAll returns all mathces
$result = $stmt->fetchAll(); # result as associtive array AND numeric array (PDO::FETCH_BOTH)
$result = $stmt->fetchAll(PDO::FETCH_ASSOC); # result as associtive array
# fetchAll returns all matches
$result = $stmt->fetchAll(); # result as associative array AND numeric array (PDO::FETCH_BOTH)
$result = $stmt->fetchAll(PDO::FETCH_ASSOC); # result as associative array
$result = $stmt->fetchAll(PDO::FETCH_NUM); # result as array
$result = $stmt->fetchAll(PDO::FETCH_OBJ); # result as object of stdClass
$result = $stmt->fetchAll(PDO::FETCH_CLASS, ClassName::class); # result as object of a specific class
@ -90,13 +90,13 @@ $stmt->debugDumpParams(); # print the SQL query that has been sent to the datab
```php
$db = SQLite3("db_file.sqlite3"); // connection
$stmt = $db->prepare("SELECT fields FROM tables WHERE field <operator> :marker"); // preapre query
$stmt = $db->prepare("SELECT fields FROM tables WHERE field <operator> :marker"); // prepare query
$stmt->bindParam(":marker", $variable); // param binding
$result = $stmt->execute(); // retireve records
$result = $stmt->execute(); // retrieve records
$result->finalize(); // close result set, recommended calling before another execute()
$records = $results->fetchArray(SQLITE3_ASSOC); // extract records as array (flase if no results)
$records = $results->fetchArray(SQLITE3_ASSOC); // extract records as array (false if no results)
```
**NOTE**: Result set objects retrieved by calling `SQLite3Stmt::execute()` on the same statement object are not independent, but rather share the same underlying structure. Therefore it is recommended to call `SQLite3Result::finalize()`, before calling `SQLite3Stmt::execute()` on the same statement object again.

6
PHP/Dependecy Injection.md
View file

@ -14,13 +14,13 @@ class Foo
## Dependency Injection Container
The **Dependecy Injection Container** (DIC) allow to archive all the dependencies in a single `Container` class. Some offer automatic resolution of the dependecies.
The **Dependency Injection Container** (DIC) allow to archive all the dependencies in a single `Container` class. Some offer automatic resolution of the dependencies.
## [PHP-DI](https://php-di.org/)
The dependency injection container for humans. Installation: `composer require php-di/php-di`
- **Autowire** functionality: the ability of the container to create and inject the dependecy automatically.
- **Autowire** functionality: the ability of the container to create and inject the dependency automatically.
- Use of [Reflection](https://www.php.net/manual/en/intro.reflection.php)
- Configuration of the container through annotations & PHP code.
@ -57,7 +57,7 @@ class Foo
// config.php
use Psr\Container\ContainerInterface;
// config "primitrive" dependencies (dependecy => construct & return)
// config "primitive" dependencies (dependency => construct & return)
return [
'dsn' => 'sqlite:db.sq3',
PDO::class => function(ContainerInterface $c) {

62
PHP/PHP.md
View file

@ -26,7 +26,7 @@ In `config.php`:
```php
//config.php
//store configuration options in associtive array
//store configuration options in associative array
return [
setting => value,
setting = value,
@ -34,7 +34,7 @@ return [
```
```php
$config = include "config.php"; // retireve config and store into variable
$config = include "config.php"; // retrieve config and store into variable
```
## Namespace
@ -42,7 +42,7 @@ $config = include "config.php"; // retireve config and store into variable
[PSR-4 Spec](https://www.php-fig.org/psr/psr-4/)
```php
namespace Foo\Bar\Baz; # set nemespace for all file contents, \ for nested namespaces
namespace Foo\Bar\Baz; # set namespace for all file contents, \ for nested namespaces
use <PHP_Class> # using a namespace hides standard php classes (WHY?!?)
@ -54,7 +54,7 @@ namespace Foo\Bar\Baz {
};
Foo\Bar\Baz\func(); # use function from Foo\Bar\Baz withous USE instruction
Foo\Bar\Baz\func(); # use function from Foo\Bar\Baz without USE instruction
use Foo\Bar\Baz\func; # import namespace
func(); # use function from Foo\Bar\Baz
@ -106,7 +106,7 @@ if (!function_exists('readline')) {
## Variables
```php
$varibleName = value; # weakly typed
$variableName = value; # weakly typed
echo gettype(&variable); # output type of variable
var_dump($var); # prints info of variable (bit dimension, type & value)
@ -159,7 +159,7 @@ $c = 7E-10; // 0.0000000007
## Strings
A string is a sequrnce of ASCII characters. In PHP a string is an array of charachters.
A string is a sequence of ASCII characters. In PHP a string is an array of characters.
### String Concatenation
@ -172,10 +172,10 @@ $string1 .= $string2; # method 2
```php
strlen($string); # returns the string length
strpos($string, 'substring'); # position of dubstring in string
substr($string, start, len); # ectract substring of len from position start
strtoupper($string); # transfrorm to uppercase
strtolower($string); # transform to lowerchase
strpos($string, 'substring'); # position of substring in string
substr($string, start, len); # extract substring of len from position start
strtoupper($string); # transform to uppercase
strtolower($string); # transform to lowercase
explode(delimiter, string); # return array of substrings
@ -205,8 +205,8 @@ Heterogeneous sequence of values.
$array = (sequence_of_items); # array declaration and valorization
$array = [sequence_of_items]; # array declaration and valorization
# index < 0 selecst items starting from the last
$array[index]; # accest to the items
# index < 0 selects items starting from the last
$array[index]; # access to the items
$array[index] = value; # array valorization (can add items)
$array[] = value; # value appending
@ -279,7 +279,7 @@ $italianDay["Mon"]; # evaluates to Lunedì
## Conditional Instructions
### Conditional Opeartors
### Conditional Operators
| Operator | Operation |
| ----------- | ------------------------ |
@ -299,13 +299,13 @@ With `==` a string evaluates to `0`.
### Logical Operators
| Operator | Example | Result |
| -------- | ----------- | ---------------------------------------------------- | --- | ------------------------------------ |
| -------- | ----------- | ---------------------------------------------------- |
| `and` | `$a and $b` | TRUE if both `$a` and `$b` are TRUE. |
| `or` | `$a or $b` | TRUE if either `$a` or `$b` is TRUE. |
| `xor` | `$a xor $b` | TRUE if either `$a` or `$b` is TRUE, but _not both_. |
| `not` | `!$a` | TRUE if `$a` is _not_ TRUE. |
| `and` | `$a && $b` | TRUE if both `$a` and `$b` are TRUE. |
| `or` | `$a | | $b` | TRUE if either `$a` or `$b` is TRUE. |
| `or` | `$a || $b` | TRUE if either `$a` or `$b` is TRUE. |
### Ternary Operator
@ -317,7 +317,7 @@ condition ?: result_if_false;
### NULL Coalesce
```php
$var1 = $var2 ?? value; # if variable == NULL assign value, othervise return value of $var2
$var1 = $var2 ?? value; # if variable == NULL assign value, otherwise return value of $var2
# equivalent to
$var1 = isset($var2) ? $var2 : value
@ -328,7 +328,7 @@ $var1 = isset($var2) ? $var2 : value
```php
$a <=> $b;
# equivalen to
# equivalent to
if $a > $b
return 1;
if $a == $b
@ -445,7 +445,7 @@ do {
[Function Docstring](https://make.wordpress.org/core/handbook/best-practices/inline-documentation-standards/php/)
Parameters with default values are optional in the function call and must be the last ones in the function declaration. Return type is optional if type checking is diasbled.
Parameters with default values are optional in the function call and must be the last ones in the function declaration. Return type is optional if type checking is disabled.
```php
declare(strict_types=1); # activates type checking
@ -516,7 +516,7 @@ function functionName (?type $parameter): ?Type
## Anonymous Functions (Closure)
```php
# declaration and assignement to variable
# declaration and assignment to variable
$var = function (type $parameter) {
# code here
};
@ -576,12 +576,12 @@ class ClassName
const CONSTANT = value; # public by default
public $attribute; # null by default if not assigned
public Type $attribute; # specifing the type is optional, it will be enforced if present
public Type $attribute; # specifying the type is optional, it will be enforced if present
# class constructor
public function __construct(value)
{
$this->attrivute = value
$this->attribute = value
}
public getAttribute(): Type
@ -650,7 +650,7 @@ class ClassName
### Inheritance
If a class is defind `final` it can't be extended.
If a class is defined `final` it can't be extended.
If a function is declared `final` it can't be overridden.
```php
@ -664,7 +664,7 @@ class Child extends Parent
### Abstract Class
Abstract calsses cannot be instantiated;
Abstract classes cannot be instantiated;
```php
abstract class ClassName
@ -701,7 +701,7 @@ class ClassName implements InterfaceName {
`Traits` allows the reutilization of code inside different classes without links of inheritance.
It can be used to mitigate the problem of _multiple inheritance_, which is absent in PHP.
In case of functions name conflic it's possible to use `insteadof` to specify which function to use. It's also possible to use an _alias_ to resolve the conflicts.
In case of functions name conflict it's possible to use `insteadof` to specify which function to use. It's also possible to use an _alias_ to resolve the conflicts.
```php
trait TraitName {
@ -729,7 +729,7 @@ $obj->method(new class implements Interface {
## Serialization & JSON
```php
$serialized = serialize($obj); # serailization
$serialized = serialize($obj); # serialization
$obj = unserialize($serialized); # de-serialization
$var = json_decode(string $json, bool $associative); # Takes a JSON encoded string and converts it into a PHP variable.ù
@ -752,7 +752,7 @@ file_get_contents(filename); // read whole file
```php
preg_match('/PATTERN/', string $subject, array $matches); # returns 1 if the pattern matches given subject, 0 if it does not, or FALSE if an error occurred
# $mathces[0] = whole matched string
# $matches[0] = whole matched string
# $matches[i] = i-th group of the regex
```
@ -805,7 +805,7 @@ Algorithms currently supported:
- **threads** (integer) - Number of threads to use for computing the Argon2 hash. Defaults to PASSWORD_ARGON2_DEFAULT_THREADS.
```php
password_hash($passwrd, $algorithm); # create a new password hash using a strong one-way hashing algorithm.
password_hash($password, $algorithm); # create a new password hash using a strong one-way hashing algorithm.
password_verify($password, $hash); # Verifies that a password matches a hash
```
@ -814,7 +814,7 @@ password_verify($password, $hash); # Verifies that a password matches a hash
Types of PHP errors:
- **Fatal Error**: stop the execution of the program.
- **Warning**: generataed at runtime, does not stop the execution (non-blocking).
- **Warning**: generated at runtime, does not stop the execution (non-blocking).
- **Notice**: informative errors or messages, non-blocking.
```php
@ -849,7 +849,7 @@ ini_set("error_log", "path\\error.log"); // set log file
```php
// generate E_USER_ errors
trigger_error("message"); // defaul type: E_USER_NOTICE
trigger_error("message"); // default type: E_USER_NOTICE
trigger_error("message", E_USER_<Type>);
trigger_error("Deprecated Function", E_USER_DEPRECATED);
@ -873,9 +873,9 @@ PHP offers the possibility to handle errors with the _exception model_.
```php
try {
// dangerous code
} catch(ExcpetionType1 | ExceptionType2 $e) {
} catch(ExceptionType1 | ExceptionType2 $e) {
printf("Errore: %s", $e->getMessage());
} catch(Excpetion $e) {
} catch(Exception $e) {
// handle or report exception
}

2
PHP/PSR-7.md
View file

@ -2,7 +2,7 @@
## [PSR-7](https://www.php-fig.org/psr/psr-7/)
Standard of the PHP Framework Interop Group that defines common interafces for handling HTTP messages.
Standard of the PHP Framework Interop Group that defines common interfaces for handling HTTP messages.
- `Psr\Http\Message\MessageInterface`
- `Psr\Http\Message\RequestInterface`

4
PHP/Simple_MVC/Simple_MVC.md
View file

@ -23,7 +23,7 @@ composer create-project ezimuel/simple-mvc
| |- route.php --> routing
|- public
| |- img
| |- index.php --> app entrypoint
| |- index.php --> app entry-point
|- src
| |- Model
| |- View --> Plates views
@ -33,7 +33,7 @@ composer create-project ezimuel/simple-mvc
| |- Controller
```
### `indedx.php`
### `index.php`
```php
<?php

10
PHP/Templates with Plates.md
View file

@ -4,7 +4,7 @@
To separate HTML code and PHP code it's possible to use **templates** with markers for variable substitution.
Variables are created in the PHP code and are passed to the template in the **rendering** phase.
The server transmitts only the `index.php` file to the user. The php file renders the templates as needed.
The server transmits only the `index.php` file to the user. The php file renders the templates as needed.
```html
<html>
@ -20,7 +20,7 @@ The server transmitts only the `index.php` file to the user. The php file render
## [Plates](https://platesphp.com/)
Plates is a templete engine for PHP. A templete engine permits to separate the PHP code (businnes logic) from the HTML pages.
Plates is a template engine for PHP. A template engine permits to separate the PHP code (business logic) from the HTML pages.
Installation through composer: `composer require league/plates`.
@ -51,14 +51,14 @@ echo $templates->render("template_name", [
</html>
```
Variables in the template are created through an associtve array `key => value`. The key (`"key"`) becomes a variable (`$key`) in the template.
Variables in the template are created through an associative array `key => value`. The key (`"key"`) becomes a variable (`$key`) in the template.
### Layout
It's possible to create a layout (a model) for a group of pages to make that identical save for the contents.
In a layout it's possible to create a section called **content** that identifies content that can be specified at runtime.
**NOTE**: Sinsce only the template has the data passed eventual loops have to be done there.
**NOTE**: Since only the template has the data passed eventual loops have to be done there.
```php
# index.php
@ -94,7 +94,7 @@ echo $template->render('template_name', [ "marker" => value, ... ]);
It's necessary to verify that the output is in the necessary format.
Plates offerts `$this->escape()` or `$this->e()` to validate the output.
Plates offers `$this->escape()` or `$this->e()` to validate the output.
In general the output validation allows to prevent [Cross-Site Scripting][owasp-xss] (XSS).
[owasp-xss]: https://owasp.org/www-community/attacks/xss/

22
PHP/Unit Testing.md
View file

@ -43,7 +43,7 @@ PHPUnit can be configured in a XML file called `phpunit.xml`:
### Test Structure
**PHPUnit** tests are grouped in classes suffixed with `Test`. Each class *extends* `PHPUnit\Framework\TestCase`.
A test is a method of a *test class* prefized with `test`.
A test is a method of a *test class* prefixed with `test`.
PHPUnit is executed from the command line with `vendor/bin/phpunit --colors`.
```php
@ -85,10 +85,10 @@ class FilterTest extends TestCase
- `assertFalse()`: verifies that the element is false
- `assertEmpty()`: verifies that the element is empty
- `assertEquals()`: verifies that the two elements are equal
- `assertGreaterThan()`: verifies that the element is greter than ...
- `assertGreaterThan()`: verifies that the element is greater than ...
- `assertContains()`: verifies that the element is contained in an array
- `assertInstanceOf()`: verifies that the element is an instance of a specific class
- `assertArrayHasKey(mixed $key, array $array)`: verify taht a sopecific key is in the array
- `assertArrayHasKey(mixed $key, array $array)`: verify that a specific key is in the array
### [PHPUnit Testing Exceptions](https://phpunit.readthedocs.io/en/9.3/writing-tests-for-phpunit.html#testing-exceptions)
@ -98,13 +98,13 @@ public function testAggiungiEsameException(string $esame)
$this->expectException(Exception::class);
$this->expectExceptionMessage("exception_message");
// execute code that sould throw an exception
// execute code that should throw an exception
}
// https://github.com/sebastianbergmann/phpunit/issues/2484#issuecomment-648822531
public function testExceptionNotTrown()
public function testExceptionNotThrown()
{
$exceptioWasTrown = false;
$exceptionWasThrown = false;
try
{
@ -112,10 +112,10 @@ public function testExceptionNotTrown()
}
catch (EsameException $e)
{
$exceptioWasTrown = true;
$exceptionWasThrown = true;
}
$this->assertFalse($exceptioWasTrown);
$this->assertFalse($exceptionWasThrown);
}
// same as
@ -168,7 +168,7 @@ class DataTest extends TestCase
$this->assertEquals($expected, $a + $b);
}
// test recieves array contents as input
// test receives array contents as input
public function provider()
{
// must return array of arrays
@ -178,7 +178,7 @@ class DataTest extends TestCase
];
}
// test recieves array of arrays as input
// test receives array of arrays as input
public function provideArrayOfArrays()
{
return [
@ -226,5 +226,5 @@ class UnitTest extends TestCase
### Code Coverage (needs [XDebug](https://xdebug.org/))
```ps1
vendor/bin/phpunit --coverage-text # code cverage analisys in the terminal
vendor/bin/phpunit --coverage-text # code coverage analysis in the terminal
```

18
PHP/Web.md
View file

@ -12,7 +12,7 @@ PHP -S <ip:post> file.php # redirect requests to single file
## HTTP Methods
Handling of HTTP requests happend using the following global variables:
Handling of HTTP requests happens using the following global variables:
- `$_SERVER`: info on request headers, version, URL path and method (dict)
- `$_GET`: parameters of get request (dict)
@ -54,7 +54,7 @@ if (! move_uploaded_file($_FILES['photo']['tmp_name'], $path)) {
exit();
}
echo'<h1>File succesfully sent</h1>';
echo'<h1>File successfully sent</h1>';
```
### `$_SERVER`
@ -80,8 +80,8 @@ $_SERVER["HTTP_USER_AGENT"];
All sites **must** have a page for the consensus about using cookies.
**Cookies** are HTTP headers used to memorize key-value info *on the client*. They are sent from the server to the client to keep track of info on the user that is visting the website.
When a client recieves a HTTP response that contains `Set-Cookie` headers it has to memorize that info and reuse them in future requests.
**Cookies** are HTTP headers used to memorize key-value info *on the client*. They are sent from the server to the client to keep track of info on the user that is visiting the website.
When a client receives a HTTP response that contains `Set-Cookie` headers it has to memorize that info and reuse them in future requests.
```http
Set-Cookie: <cookie-name>=<cookie-value>
@ -95,7 +95,7 @@ Set-Cookie: <cookie-name>=<cookie-value>; HttpOnly
Anyone can modify the contents of a cookie; for this reason cookies **must not contain** *personal or sensible info*.
When a clien has memorized a cookie, it is sent in successive HTTP requests through the `Cookie` header.
When a client has memorized a cookie, it is sent in successive HTTP requests through the `Cookie` header.
```http
Cookie: <cookie-name>=<cookie-value>
@ -114,7 +114,7 @@ string $name,
[ bool $httponly = false ] // accessible only through http (no js, ...)
)
// examle: memorize user-id 112 with 24h expiry for site example.com
// example: memorize user-id 112 with 24h expiry for site example.com
setcookie ("User-id", "112", time() + 3600*24, "/", "example.com");
// check if a cookie exists
@ -123,12 +123,12 @@ if(isset($_COOKIE["cookie_name"])) {}
### [$_SESSION](https://www.php.net/manual/en/ref.session.php)
**Sessions** are info memorized *on the server* assoiciated to the client that makes an HTTP request.
**Sessions** are info memorized *on the server* associated to the client that makes an HTTP request.
PHP generates a cookie named `PHPSESSID` containing a *session identifier* and an *hash* generated from `IP + timestamp + pseudo-random number`.
To use the session it's necesary to recall the function `session_start()` at the beginning of a PHP script that deals with sessions.
After starting the session information in be savend in the `$_SESSION` array.
To use the session it's necessary to recall the function `session_start()` at the beginning of a PHP script that deals with sessions.
After starting the session information in be saved in the `$_SESSION` array.
```php
$_SESSION["key"] = value; // save data in session file (serialized data)

4
PowerShell/Powershell Commands.md
View file

@ -17,8 +17,8 @@ New-Item -ItemType SymbolicLink -Path .\link -Target .\Notice.txt # create a sy
Move-Item -Path <source> -Destination <target> # move and/or rename files and folders
Copy-Item -Path <source> -Destination <target> # copy (and rename) files and folders
Test-Path "path" -PathType Container # check if the exising path exists and is a folder
Test-Path "path" -PathType Leaf # check if the exising path exists and is a file
Test-Path "path" -PathType Container # check if the existing path exists and is a folder
Test-Path "path" -PathType Leaf # check if the existing path exists and is a file
# start, list , kill processes
Start-Process -FilePath <file> # open a file with the default process/program

20
PowerShell/Powershell Scripting.md
View file

@ -47,7 +47,7 @@ $a, $b = $b, $a
# Interpolation
Write-Host "text $variable" # single quotes will not interpolate
Write-Host (<expresion>)
Write-Host (<expression>)
```
### Built-in Variables
@ -80,10 +80,10 @@ $List = @() # Empty List
$String = $List -join 'separator'
$List = $String -split 'separator'
# List comprhensions
# List comprehensions
$List = sequence | Where-Object {$_ command} # $_ is current object
$Dict = @{"a" = "apple"; "b" = "ball"} # Dict definition
$Dict["a"] = "acron" # Item update
$Dict["a"] = "acorn" # Item update
# Loop through keys
foreach ($k in $Dict.keys) {
@ -127,16 +127,16 @@ switch(variable) {
# syntax
switch [-regex|-wildcard|-exact][-casesensitive] (<value>)
{
"string"|number|variable|{ expression } { statementlist }
default { statementlist }
"string"|number|variable|{ expression } { statement_list }
default { statement_list }
}
# or
switch [-regex|-wildcard|-exact][-casesensitive] -file filename
{
"string"|number|variable|{ expression } { statementlist }
default { statementlist }
"string"|number|variable|{ expression } { statement_list }
default { statement_list }
}
```
@ -155,7 +155,7 @@ foreach (item in iterable) {
}
while (condition) {
# Code heer
# Code here
}
do {
@ -251,7 +251,7 @@ function Func {
```ps1
$args # array of passed arguments
$args[$index] # access to the argumnets
$args[$index] # access to the arguments
$args.count # number of arguments
```
@ -261,7 +261,7 @@ In `scripts.ps1`:
```ps1
param($param1, $param2, ...) # basic usage
param($param1, $param2=defvalue, ...) # with dafault values
param($param1, $param2=defvalue, ...) # with default values
param([Type] $param1, $param2, ...) # specify a type
param([Parameter(Mandatory)]$param1, $param2, ...) # setting a parameter as necessary

6
Python/Jupyter/Jupiter Notebook.md
View file

@ -4,7 +4,7 @@
`%quickref` Display the IPython Quick Reference Card
`%magic` Display detailed documentation for all of the available magic commands
`%debug` Enter the interactive debugger at the bottom of the last exception traceback
`%debug` Enter the interactive debugger at the bottom of the last exception trace-back
`%hist` Print command input (and optionally output) history
`%pdb` Automatically enter debugger after any exception
`%paste` Execute pre-formatted Python code from clipboard
@ -14,7 +14,7 @@
`%run` script.py Run a Python script inside IPython
`%prun` statement Execute statement with cProfile and report the profiler output
`%time` statement Report the execution time of single statement
`%timeit` statement Run a statement multiple times to compute an emsemble average execution time. Useful for timing code with very short execution time
`%timeit` statement Run a statement multiple times to compute an ensemble average execution time. Useful for timing code with very short execution time
`%who`, `%who_ls`, `%whos` Display variables defined in interactive namespace, with varying levels of information / verbosity
`%xdel` variable Delete a variable and attempt to clear any references to the object in the IPython internals
@ -23,7 +23,7 @@
`!cmd` Execute cmd in the system shell
`output = !cmd args` Run cmd and store the stdout in output
`%alias alias_name cmd` Define an alias for a system (shell) command
`%bookmark` Utilize IPython’s directory bookmarking system
`%bookmark` Utilize IPython's directory bookmarking system
`%cd` directory Change system working directory to passed directory
`%pwd` Return the current system working directory
`%pushd` directory Place current directory on stack and change to target directory

4
Python/Libs/CLI/click.md
View file

@ -37,7 +37,7 @@ cli.add_command(dropdb)
The `group()` decorator works like the `command()` decorator, but creates a Group object instead which can be given multiple subcommands that can be attached with `Group.add_command()`.
For simple scripts, it’s also possible to automatically attach and create a command by using the `Group.command()` decorator instead.
For simple scripts, it's also possible to automatically attach and create a command by using the `Group.command()` decorator instead.
The above script can instead be written like this:
```py
@ -54,7 +54,7 @@ def dropdb():
click.echo('Dropped the database')
```
You would then invoke the Group in your setuptools entry points or other invocations:
You would then invoke the Group in your setup-tools entry points or other invocations:
```py
if __name__ == '__main__':

66
Python/Libs/GUI/Tkinter.md
View file

@ -10,27 +10,27 @@ from tkinter import ttk # import Themed Widgets
## GEOMETRY MANAGEMENT
Putting widgets on screen
master widget --> toplevel window, frame
master widget --> top-level window, frame
slave widget --> widgets contained in master widget
geometry managers determine size and oder widget drawing properties
## EVENT HANDLING
event loop recives events from the OS
event loop receives events from the OS
customizable events provide a callback as a widget configuration
```py
widget.bind('event', function) # method to capture any event and than execute an arbitrary piece of code (generally a functio or lambda)
widget.bind('event', function) # method to capture any event and than execute an arbitrary piece of code (generally a function or lambda)
```
VIRTUAL EVENT --> hig level event genearted by widget (listed in widget docs)
VIRTUAL EVENT --> hig level event generated by widget (listed in widget docs)
## WIDGETS
"idgets are objects and all things on screen. All widgets are children of a window.
Widgets are objects and all things on screen. All widgets are children of a window.
```py
widget_name = tk_object(parent_window) # widget is insetred into widget hierarchy
widget_name = tk_object(parent_window) # widget is inserted into widget hierarchy
```
## FRAME WIDGET
@ -40,7 +40,7 @@ Displays a single rectangle, used as container for other widgets
```py
frame = ttk.Frame(parent, width=None, height=None, borderwidth=num:int)
# BORDERWIDTH: sets frame border width (default: 0)
# width, height MUST be specified if frame is empty, otherwise determinded by parent geometry manager
# width, height MUST be specified if frame is empty, otherwise determined by parent geometry manager
```
### FRAME PADDING
@ -49,7 +49,7 @@ Extra space inside widget (margin).
```py
frame['padding'] = num # same padding for every border
frame['padding'] = (horizzontal, vertical) # set horizontal THEN vertical padding
frame['padding'] = (horizontal, vertical) # set horizontal THEN vertical padding
frame['padding'] = (left, top, right, bottom) # set left, top, right, bottom padding
# RELIEF: set border style, [flat (default), raised, sunken, solid, ridge, groove]
@ -58,7 +58,7 @@ frame['relief'] = border_style
## LABEL WIDGET
Display tetx or image without interactivity.
Display text or image without interactivity.
```py
label = ttk.Label(parent, text='label text')
@ -67,7 +67,7 @@ label = ttk.Label(parent, text='label text')
### DEFINING UPDATING LABEL
```py
var = StringVar() # variable containing text, watchs for changes. Use get, set methods to interact with the value
var = StringVar() # variable containing text, watches for changes. Use get, set methods to interact with the value
label['textvariable'] = var # attach var to label (only of type StringVar)
var.set("new text label") # change label text
```
@ -105,7 +105,7 @@ label['anchor'] = compass_direction #compass_direction: n, ne, e, se, s, sw, w,
```py
# use \n for multi line text
label['wraplength'] = size # max line lenght
label['wraplength'] = size # max line length
```
### CONTROL TEXT JUSTIFICATION
@ -114,8 +114,8 @@ label['wraplength'] = size # max line lenght
label['justify'] = value #value: left, center, right
label['relief'] = label_style
label['foreground'] = color # color pased with name or HEX RGB codes
label['background'] = color # color pased with name or HEX RGB codes
label['foreground'] = color # color passed with name or HEX RGB codes
label['background'] = color # color passed with name or HEX RGB codes
```
### FONT STYLE (use with caution)
@ -129,7 +129,7 @@ Fonts:
- TkDefaultFont -- default for all GUI items
- TkTextFont -- used for entry widgets, listboxes, etc
- TkFixedFont -- standar fixed-width font
- TkFixedFont -- standard fixed-width font
- TkMenuFont -- used for menu items
- TkHeadingFont -- for column headings in lists and tables
- TkCaptionFont -- for window and dialog caption bars
@ -159,7 +159,7 @@ button.invoke() # button activation in the program
### BUTTON STATE
Activate (interagible) or deactivate (not interagible) the widget.
Activate or deactivate the widget.
```py
button.state(['disabled']) # set the disabled flag, disabling the button
@ -172,7 +172,7 @@ button.instate(['!disabled'], cmd) # execute 'cmd' if the button is not disable
## CHECKBUTTON
Button with binary value of some kind (e.g a toggle) and also invokes a comman callback
Button with binary value of some kind (e.g a toggle) and also invokes a command callback
```py
checkbutton_var = TkVarType
@ -182,9 +182,9 @@ check = ttk.Checkbutton(parent, text='button text', command=action_performed, va
### WIDGET VALUE
Variable option holds value of button, updated by widget toggle.
EFAULT: 1 (while checked), 0 (while unchecked)
`onvalue`, `offvalue` are used to personalize cheched and uncheched values
if linked variable is empry or different from on-offvalue the state flag is set to alternate
DEFAULT: 1 (while checked), 0 (while unchecked)
`onvalue`, `offvalue` are used to personalize checked and unchecked values
if linked variable is empty or different from on-off value the state flag is set to alternate
checkbutton won't set the linked variable (MUST be done in the program)
### CONFIG OPTIONS
@ -245,7 +245,7 @@ radio.instate(['flag'])
## COMBOBOX
Drop-down list of avaiable options.
Drop-down list of available options.
```py
combobox_var = StringVar()
@ -253,7 +253,7 @@ combo = ttk.Combobox(parent, textvariable=combobox_var)
combobox.get() # return combobox current value
combobox.set(value) # set combobox new value
combobox.current() # returns which item in the predefined values list is selected (0-based index of the provided list, -1 if not in the list)
#combobox will generate a bind-able <ComboxboSelected> virtual event whenever the value changes
#combobox will generate a bind-able <ComboboxSelected> virtual event whenever the value changes
combobox.bind('<<ComboboxSelected>>', function)
```
@ -271,7 +271,7 @@ Display list of single-line items, allows browsing and multiple selection (part
```py
lstbx = Listbox(parent, height=num, listvariable=item_list:list)
# listvariable links a variable (MUST BE a list) to the listbox, each elemenmt is a item of the listbox
# listvariable links a variable (MUST BE a list) to the listbox, each element is a item of the listbox
# manipulation of the list changes the listbox
```
@ -292,7 +292,7 @@ lstbx.curselection() # returns list of indices of selected items
scroll = ttk.Scrollbar(parent, orient=direction, command=widget.view)
# ORIENT: VERTICAL, HORIZONTAL
# WIDGET.VIEW: .xview, .yview
# NEEDS ASSOCITED WIDGET SCROLL CONFIG
# NEEDS ASSOCIATED WIDGET SCROLL CONFIG
widget.configure(xscrollcommand=scroll.set)
widget.configure(yscrollcommand=scroll.set)
```
@ -324,10 +324,10 @@ txt.delete(start, end) # delete range of text
Feedback about progress of lenghty operation.
```py
progbar = ttk.Progressbar(parent, orient=direction, lenght=num:int, value=num, maximum=num:float mode=mode)
progbar = ttk.Progressbar(parent, orient=direction, length=num:int, value=num, maximum=num:float mode=mode)
# DIRECTION: VERTICAL, HORIZONTAL
# MODE: determinate (relative progress of completion), indeterminate (no estimate of completion)
# LENGHT: dimension in pixel
# LENGTH: dimension in pixel
# VALUE: sets the progress, updates the bar as it changes
# MAXIMUM: total number of steps (DEFAULT: 100)
```
@ -342,7 +342,7 @@ progbar.step(amount) # increment value of given amount (DEFAULT: 1.0)
```py
progbar.start() # starts progressbar
progbar.stop() #stopos progressbar
progbar.stop() #stoops progressbar
```
## SCALE
@ -350,7 +350,7 @@ progbar.stop() #stopos progressbar
Provide a numeric value through direct manipulation.
```py
scale = ttk.Scale(parent, orient=DIR, lenght=num:int, from_=num:float, to=num:float, command=cmd)
scale = ttk.Scale(parent, orient=DIR, length=num:int, from_=num:float, to=num:float, command=cmd)
# COMMAND: calls cmd at every scale change, appends current value to func call
scale['value'] # set or read current value
scale.set(value) # set current value
@ -364,9 +364,9 @@ Choose numbers. The spinbox choses item from a list, arrows permit cycling lits
```py
spinval = StringVar()
spin = Spinbox(parent, from_=num, to=num, textvariable=spinval, increment=num, value=lst, wrap=boolean)
# INCREMENT specifies incremend\decremenment by arrow button
# INCREMENT specifies increment\decrement by arrow button
# VALUE: list of items associated with the spinbox
# WRAP: boolean value determining if value shuld wrap around if beyond start-end value
# WRAP: boolean value determining if value should wrap around if beyond start-end value
```
## GRID GEOMETRY MANAGER
@ -424,7 +424,7 @@ tlw = Toplevel(parent) # parent of root window, no need to grid it
window.destroy()
# can destroy every widget
# destroing parent also destroys it's children
# destroying parent also destroys it's children
```
### CHANGING BEHAVIOR AND STYLE
@ -436,7 +436,7 @@ window.title('new title') # sets title
# SIZE AND LOCATION
window.geometry(geo_specs)
'''full geomtry specification: width * height +- x +- y (actual coordinates of screen)
'''full geometry specification: width * height +- x +- y (actual coordinates of screen)
+x --> x pixels from left edge
-x --> x pixels from right edge
+y --> y pixels from top edge
@ -454,7 +454,7 @@ window.lift(otherwin) # relative to other window
window.lower() # absolute position
window.lower(otherwin) # relative to other window
# RESIZION BEHAVIOR
# RESIZE BEHAVIOR
window.resizable(boolean, boolean) # sets if resizable in width (1st param) and width (2nd param)
window.minsize(num, num) # sets min width and height
window.maxsize(num, num) # sets max width and height
@ -470,7 +470,7 @@ window.deiconify() # deiconifies window
### STANDARD DIALOGS
```py
# SLECTING FILE AND DIRECTORIES
# SLEETING FILE AND DIRECTORIES
# on Windows and Mac invokes underlying OS dialogs directly
from tkinter import filedialog
filename = filedialog.askopenfilename()

4
Python/Libs/Image/Pillow.md
View file

@ -1,4 +1,4 @@
# Pillow Library Cheat Sheet
# Pillow
## Standard Imports
@ -16,7 +16,7 @@ image = Image.open(filepath, mode) # open image file (returns Image object)
image.format # image file extension
image.size # 2-tuple (width, height) in pixels
image.mode # defines number and name of bands in image, pixeld type and depth
image.mode # defines number and name of bands in image, pixel type and depth
```
## SAVING IMAGE FILE

12
Python/Libs/Image/PyCairo.md
View file

@ -1,4 +1,4 @@
# PyCarto Cheat Sheet
# PyCairo
## Definitions
@ -11,7 +11,7 @@ A `Path` is a collection of points used to create primitive shapes such as lines
In a closed path, starting and ending points meet. In an open path, starting and ending point do not meet. In PyCairo, we start with an empty path.
First, we define a path and then we make them visible by stroking and/or filling them. After each `stroke()` or `fill()` method call, the path is emptied.
We have to define a new path. If we want to keep the existing path for later drawing, we can use the `stroke_preserve()` and `fill_preserve()` methods.
A path is made of subpaths.
A path is made of sub-paths.
A `Source` is the paint we use in drawing. We can compare the source to a pen or ink that we use to draw the outlines and fill the shapes.
There are four kinds of basic sources: colors, gradients, patterns, and images.
@ -83,7 +83,7 @@ context.set_source_rgb(red, green, blue)
`context.new_sub_path()` begins a new sub-path. Note that the existing path is not affected. After this call there will be no current point.
In many cases, this call is not needed since new sub-paths are frequently started with `Context.move_to()`.
A call to `new_sub_path()` is particularly useful when beginning a new sub-path with one of the `Context.arc()` calls.
This makes things easier as it is no longer necessary to manually compute the arc’s initial coordinates for a call to `Context.move_to()`.
This makes things easier as it is no longer necessary to manually compute the arc's initial coordinates for a call to `Context.move_to()`.
### Stroke
@ -99,7 +99,7 @@ After `fill()`, the current path will be cleared from the Context.
`context.set_fill_rule(fill_rule)` set a FILL RULE to the cairo context.
For both fill rules, whether or not a point is included in the fill is determined by taking a ray from that point to infinity and looking at intersections with the path.
The ray can be in any direction, as long as it doesn’t pass through the end point of a segment or have a tricky intersection such as intersecting tangent to the path.
The ray can be in any direction, as long as it doesn't pass through the end point of a segment or have a tricky intersection such as intersecting tangent to the path.
(Note that filling is not actually implemented in this way. This is just a description of the rule that is applied.)
* `cairo.FILL_RULE_WINDING` (default):
@ -138,9 +138,9 @@ Font Weights:
## Creating the image
```py
surface.show_page() # Emits and clears the current page for backends that support multiple pages. Use copy_page() if you don’t want to clear the page.
surface.show_page() # Emits and clears the current page for backends that support multiple pages. Use copy_page() if you don't want to clear the page.
surface.copy_page() # Emits the current page for backends that support multiple pages, but doesn’t clear it, so that the contents of the current page will be retained for the next page. Use show_page() if you want to get an empty page after the emission.
surface.copy_page() # Emits the current page for backends that support multiple pages, but doesn't clear it, so that the contents of the current page will be retained for the next page. Use show_page() if you want to get an empty page after the emission.
surface.write_to_png("filename") # Writes the contents of Surface to filename as a PNG image
```

48
Python/Libs/Math/NumPy.md
View file

@ -16,7 +16,7 @@ Unless explicitly specified `np.array` tries to infer a good data type for the a
The data type is stored in a special dtype object.
```py
var = np.array(sequence) # createa array
var = np.array(sequence) # creates array
var = np.asarray(sequence) # convert input to array
var = np.ndarray(*sequence) # creates multidimensional array
var = np.asanyarray(*sequence) # convert the input to an ndarray
@ -53,12 +53,12 @@ The numerical `dtypes` are named the same way: a type name followed by a number
| complex64, complex128, complex256 | c8, c16, c32 | Complex numbers represented by two 32, 64, or 128 floats, respectively |
| bool | ? | Boolean type storing True and False values |
| object | O | Python object type |
| string_ | `S<num>` | Fixed-length string type (1 byte per character), `<num>` is string lenght |
| unicode_ | `U<num>` | Fixed-length unicode type, `<num>` is lenght |
| string_ | `S<num>` | Fixed-length string type (1 byte per character), `<num>` is string length |
| unicode_ | `U<num>` | Fixed-length unicode type, `<num>` is length |
## OPERATIONS BETWEEN ARRAYS AND SCALARS
Any arithmetic operations between equal-size arrays applies the operation elementwise.
Any arithmetic operations between equal-size arrays applies the operation element-wise.
array `+` scalar --> element-wise addition (`[1, 2, 3] + 2 = [3, 4, 5]`)
array `-` scalar --> element-wise subtraction (`[1 , 2, 3] - 2 = [-2, 0, 1]`)
@ -73,7 +73,7 @@ array_1 `/` array_2 --> element-wise division (`[1, 2, 3] / [3, 2, 1] = [0.33, 1
## SHAPE MANIPULATION
```py
np.reshape(array, newshape) # changes the shape of the array
np.reshape(array, new_shape) # changes the shape of the array
np.ravel(array) # returns the array flattened
array.resize(shape) # modifies the array itself
array.T # returns the array transposed
@ -87,7 +87,7 @@ np.swapaxes(array, first_axis, second_axis) # interchange two axes of an array
```py
np.vstack((array1, array2)) # takes tuple, vertical stack of arrays (column wise)
np.hstack((array1, array2)) # takes a tuple, horizontal stack of arrays (row wise)
np.dstack((array1, array2)) # takes a tuple, depth wise stack of arrays (3rd dimesion)
np.dstack((array1, array2)) # takes a tuple, depth wise stack of arrays (3rd dimension)
np.stack(*arrays, axis) # joins a sequence of arrays along a new axis (axis is an int)
np.concatenate((array1, array2, ...), axis) # joins a sequence of arrays along an existing axis (axis is an int)
```
@ -95,32 +95,32 @@ np.concatenate((array1, array2, ...), axis) # joins a sequence of arrays along a
## SPLITTING ARRAYS
```py
np.split(array, indices) # splits an array into equalli long sub-arrays (indices is int), if not possible raises error
np.split(array, indices) # splits an array into equall7 long sub-arrays (indices is int), if not possible raises error
np.vsplit(array, indices) # splits an array equally into sub-arrays vertically (row wise) if not possible raises error
np.hsplit(array, indices) # splits an array equally into sub-arrays horizontally (column wise) if not possible raises error
np.dsplit(array, indices) # splits an array into equally sub-arrays along the 3rd axis (depth) if not possible raises error
np.array_split(array, indices) # splits an array into sub-arrays, arrays can be of different lenghts
np.array_split(array, indices) # splits an array into sub-arrays, arrays can be of different lengths
```
## VIEW()
```py
var = array.view() # creates a new array that looks at the same data
# slicinga returnas a view
# view shapes are separated but assignement changes all arrays
# slicing returns a view
# view shapes are separated but assignment changes all arrays
```
## COPY()
```py
var = array.copy() # creates a deepcopy of the array
var = array.copy() # creates a deep copy of the array
```
## INDEXING, SLICING, ITERATING
1-dimensional --> sliced, iterated and indexed as standard
n-dimensinal --> one index per axis, index given in tuple separated by commas `[i, j] (i, j)`
dots (`...`) represent as meny colons as needed to produce complete indexing tuple
n-dimensional --> one index per axis, index given in tuple separated by commas `[i, j] (i, j)`
dots (`...`) represent as many colons as needed to produce complete indexing tuple
- `x[1, 2, ...] == [1, 2, :, :, :]`
- `x[..., 3] == [:, :, :, :, 3]`
@ -134,7 +134,7 @@ iteration on first index, use .flat() to iterate over each element
## UNIVERSAL FUNCTIONS (ufunc)
Functions that performs elemen-wise operations (vectorization).
Functions that performs element-wise operations (vectorization).
```py
np.abs(array) # vectorized abs(), return element absolute value
@ -151,7 +151,7 @@ np.ceil(array) # vectorized ceil()
np.floor(array) # vectorized floor()
np.rint(array) # vectorized round() to nearest int
np.modf(array) # vectorized divmod(), returns the fractional and integral parts of element
np.isnan(array) # vectorized x == NaN, return bollean array
np.isnan(array) # vectorized x == NaN, return boolean array
np.isinf(array) # vectorized test for positive or negative infinity, return boolean array
np.isfineite(array) # vectorized test fo finiteness, returns boolean array
np.cos(array) # vectorized cos(x)
@ -163,7 +163,7 @@ np.tanh(array) # vectorized tanh(x)
np.arccos(array) # vectorized arccos(x)
np.arcsinh(array) # vectorized arcsinh(x)
np.arctan(array) # vectorized arctan(x)
np.arccosh(array) # vectorized arccos(x)
np.arccosh(array) # vectorized arccosh(x)
np.arcsinh(array) # vectorized arcsin(x)
np.arctanh(array) # vectorized arctanh(x)
np.logical_not(array) # vectorized not(x), equivalent to -array
@ -246,13 +246,13 @@ np.setxor1d() # Set symmetric differences; elements that are in either of the a
## FILE I/O WITH ARRAYS
```py
np.save(file, array) # save array to binary file in .npy fromat
np.savez(file, *array) # saveseveral arrays into a single file in uncompressed .npz format
np.save(file, array) # save array to binary file in .npy format
np.savez(file, *array) # save several arrays into a single file in uncompressed .npz format
np.savez_compressed(file, *args, *kwargs) # save several arrays into a single file in compressed .npz format
# *ARGS: arrays to save to the file. arrays will be saved with names “arr_0”, “arr_1”, and so on
# *ARGS: arrays to save to the file. arrays will be saved with names "arr_0", "arr_1", and so on
# **KWARGS: arrays to save to the file. arrays will be saved in the file with the keyword names
np.savetxt(file, X, fmt="%.18e", delimiter=" ") # save arry to text file
np.savetxt(file, X, fmt="%.18e", delimiter=" ") # save array to text file
# X: 1D or 2D
# FMT: Python Format Specification Mini-Language
# DELIMITER: {str} -- string used to separate values
@ -272,14 +272,14 @@ np.diag(array, k=0) # extract a diagonal or construct a diagonal array
np.dot(x ,y) # matrix dot product
np.trace(array, offset=0, dtype=None, out=None) # return the sum along diagonals of the array
# OFFSET: {int} -- offest of the diagonal from the main diagonal
# OFFSET: {int} -- offset of the diagonal from the main diagonal
# dtype: {dtype} -- determines the data-type of the returned array
# OUT: {ndarray} -- array into which the output is placed
np.linalg.det(A) # compute the determinant of an array
np.linalg.eig(A) # compute the eigenvalues and right eigenvectors of a square array
np.linalg.inv(A) # compute the (multiplicative) inverse of a matrix
# Ainv satisfies dot(A, Ainv) = dor(Ainv, A) = eye(A.shape[0])
# A_inv satisfies dot(A, A_inv) = dor(A_inv, A) = eye(A.shape[0])
np.linalg.pinv(A) # compute the (Moore-Penrose) pseudo-inverse of a matrix
np.linalg.qr() # factor the matrix a as qr, where q is orthonormal and r is upper-triangular
@ -304,13 +304,13 @@ np.random.Generator.beta(a, b, size=None) # draw samples from a Beta distributi
np.random.Generator.binomial(n, p, size=None) # draw samples from a binomial distribution
# N: {int, array ints} -- parameter of the distribution, >= 0
# P: {float, attay floats} -- Parameter of the distribution, >= 0 and <= 1
# P: {float, arrey floats} -- Parameter of the distribution, >= 0 and <= 1
np.random.Generator.chisquare(df, size=None)
# DF: {float, array floats} -- degrees of freedom, > 0
np.random.Generator.gamma(shape, scale=1.0, size=None) # draw samples from a Gamma distribution
# SHAPE: {flaot, array floats} -- shape of the gamma distribution, != 0
# SHAPE: {float, array floats} -- shape of the gamma distribution, != 0
np.random.Generator.normal(loc=0.0, scale=1.0, Size=None) # draw random samples from a normal (Gaussian) distribution
# LOC: {float, all floats} -- mean ("centre") of distribution

144
Python/Libs/Math/Pandas.md
View file

@ -1,4 +1,4 @@
# Pandas Lib
# Pandas
## Basic Pandas Imports
@ -25,8 +25,8 @@ s = Series(dict) # Series created from python dict, dict keys become index valu
```py
s['index'] # selection by index label
s[condition] # return slice selected by condition
s[ : ] # slice endpoin included
s[ : ] = *value # modifi value of entire slice
s[ : ] # slice endpoint included
s[ : ] = *value # modify value of entire slice
s[condition] = *value # modify slice by condition
```
@ -35,8 +35,8 @@ s[condition] = *value # modify slice by condition
Missing data appears as NaN (Not a Number).
```py
pd.isnull(array) # retunn a Series index-bool indicating wich indexes dont have data
pd.notnull(array) # retunn a Series index-bool indicating wich indexes have data
pd.isnull(array) # return a Series index-bool indicating which indexes don't have data
pd.notnull(array) # return a Series index-bool indicating which indexes have data
array.isnull()
array.notnull()
```
@ -53,18 +53,18 @@ s.index.name = "index name" # renames index
### SERIES METHODS
```py
pd.Series.isin(self, values) # boolean Series showing whether elements in Series matcheselements in values exactly
pd.Series.isin(self, values) # boolean Series showing whether elements in Series matches elements in values exactly
# Conform Series to new index, new object produced unless the new index is equivalent to current one and copy=False
pd.Series.reindex(delf, index=None, **kwargs)
pd.Series.reindex(self, index=None, **kwargs)
# INDEX: {array} -- new labels / index
# METHOD: {none (dont fill gaps), pad (fill or carry values forward), backfill (fill or carry values backward)}-- hole filling method
# METHOD: {none (don't fill gaps), pad (fill or carry values forward), backfill (fill or carry values backward)}-- hole filling method
# COPY: {bool} -- return new object even if index is same -- DEFAULT True
# FILLVALUE: {scalar} --value to use for missing values. DEFAULT NaN
pd.Series.drop(self, index=None, **kwargs) # return Series with specified index labels removed
# INPLACE: {bool} -- if true do operation in place and return None -- DEFAULT False
# ERRORS: {ignore, raise} -- If ‘ignore’, suppress error and existing labels are dropped
# ERRORS: {ignore, raise} -- If "ignore", suppress error and existing labels are dropped
# KeyError raised if not all of the labels are found in the selected axis
pd.Series.value_counts(self, normalize=False, sort=True, ascending=False, bins=None, dropna=True)
@ -72,7 +72,7 @@ pd.Series.value_counts(self, normalize=False, sort=True, ascending=False, bins=N
# SORT: {bool} -- sort by frequency -- DEFAULT True
# ASCENDING: {bool} -- sort in ascending order -- DEFAULT False
# BINS: {int} -- group values into half-open bins, only works with numeric data
# DROPNA: {bool} -- dont include counts of NaN
# DROPNA: {bool} -- don't include counts of NaN
```
## DATAFRAME
@ -124,19 +124,19 @@ df.T # transpose
### DATAFRAME METHODS
```py
pd.DataFrame.isin(self , values) # boolean DataFrame showing whether elements in DataFrame matcheselements in values exactly
pd.DataFrame.isin(self , values) # boolean DataFrame showing whether elements in DataFrame matches elements in values exactly
# Conform DataFrame to new index, new object produced unless the new index is equivalent to current one and copy=False
pd.DataFrame.reindex(self, index=None, columns=None, **kwargs)
# INDEX: {array} -- new labels / index
# COLUMNS: {array} -- new labels / columns
# METHOD: {none (dont fill gaps), pad (fill or carry values forward), backfill (fill or carry values backward)}-- hole filling method
# METHOD: {none (don't fill gaps), pad (fill or carry values forward), backfill (fill or carry values backward)}-- hole filling method
# COPY: {bool} -- return new object even if index is same -- DEFAULT True
# FILLVALUE: {scalar} --value to use for missing values. DEFAULT NaN
pd.DataFrame.drop(self, index=None, columns=None, **kwargs) # Remove rows or columns by specifying label names
# INPLACE: {bool} -- if true do operation in place and return None -- DEFAULT False
# ERRORS: {ignore, raise} -- If ‘ignore’, suppress error and existing labels are dropped
# ERRORS: {ignore, raise} -- If "ignore", suppress error and existing labels are dropped
# KeyError raised if not all of the labels are found in the selected axis
```
@ -147,7 +147,7 @@ Holds axis labels and metadata, immutable.
### INDEX TYPES
```py
pd.Index # immutable ordered ndarray, sliceable. stortes axis labels
pd.Index # immutable ordered ndarray, sliceable. stores axis labels
pd.Int64Index # special case of Index with purely integer labels
pd.MultiIndex # multi-level (hierarchical) index object for pandas objects
pd.PeriodINdex # immutable ndarray holding ordinal values indicating regular periods in time
@ -169,27 +169,27 @@ pd.Index.hasnans # Return True if the index has NaNs
pd.Index.append(self, other) # append a collection of Index options together
pd.Index.difference(self, other, sort=None) # set difference of two Index objects
# SORT: {None (attempt sorting), False (dont sort)}
# SORT: {None (attempt sorting), False (don't sort)}
pd.Index.intersection(self, other, sort=None) # set intersection of two Index objects
# SORT: {None (attempt sorting), False (dont sort)}
# SORT: {None (attempt sorting), False (don't sort)}
pd.Index.union(self, other, sort=None) # set union of two Index objects
# SORT: {None (attempt sorting), False (dont sort)}
# SORT: {None (attempt sorting), False (don't sort)}
pd.Index.isin(self, values, level=None) # boolean array indicating where the index values are in values
pd.Index.insert(self, loc, item) # make new Index inserting new item at location
pd.Index.delete(self, loc) # make new Index with passed location(-s) deleted
pd.Index.drop(self, labels, errors='raise') # Make new Index with passed list of labels deleted
# ERRORS: {ignore, raise} -- If ‘ignore’, suppress error and existing labels are dropped
# ERRORS: {ignore, raise} -- If 'ignore', suppress error and existing labels are dropped
# KeyError raised if not all of the labels are found in the selected axis
pd.Index.reindex(self, target, **kwargs) # create index with target’s values (move/add/delete values as necessary)
# METHOD: {none (dont fill gaps), pad (fill or carry values forward), backfill (fill or carry values backward)}-- hole filling method
pd.Index.reindex(self, target, **kwargs) # create index with target's values (move/add/delete values as necessary)
# METHOD: {none (don't fill gaps), pad (fill or carry values forward), backfill (fill or carry values backward)}-- hole filling method
```
## ARITMETHIC OPERATIONS
## ARITHMETIC OPERATIONS
NumPy arrays operations preserve labels-value link.
Arithmetic operations automatically align differently indexed data.
@ -199,10 +199,10 @@ Missing values propagate in arithmetic computations (NaN `<operator>` value = Na
```py
self + other
pd.Series.add(self, other, fill_value=None) # add(), supports substituion of NaNs
pd,Series.radd(self, other, fill_value=None) # radd(), supports substituion of NaNs
pd.DataFrame.add(self, other, axis=columns, fill_value=None) # add(), supports substituion of NaNs
pd.DataFrame.radd(self, other, axis=columns, fill_value=None) # radd(), supports substituion of NaNs
pd.Series.add(self, other, fill_value=None) # add(), supports substitution of NaNs
pd,Series.radd(self, other, fill_value=None) # radd(), supports substitution of NaNs
pd.DataFrame.add(self, other, axis=columns, fill_value=None) # add(), supports substitution of NaNs
pd.DataFrame.radd(self, other, axis=columns, fill_value=None) # radd(), supports substitution of NaNs
# OTHER: {scalar, sequence, Series, DataFrame}
# AXIS: {0, 1, index, columns} -- whether to compare by the index or columns
# FILLVALUE: {None, float} -- fill missing value
@ -212,10 +212,10 @@ pd.DataFrame.radd(self, other, axis=columns, fill_value=None) # radd(), support
```py
self - other
pd.Series.sub(self, other, fill_value=None) # sub(), supports substituion of NaNs
pd.Series.radd(self, other, fill_value=None) # radd(), supports substituion of NaNs
ps.DataFrame.sub(self, other, axis=columns, fill_value=None) # sub(), supports substituion of NaNs
pd.DataFrame.rsub(self, other, axis=columns, fill_value=None) # rsub(), supports substituion of NaNs
pd.Series.sub(self, other, fill_value=None) # sub(), supports substitution of NaNs
pd.Series.radd(self, other, fill_value=None) # radd(), supports substitution of NaNs
ps.DataFrame.sub(self, other, axis=columns, fill_value=None) # sub(), supports substitution of NaNs
pd.DataFrame.rsub(self, other, axis=columns, fill_value=None) # rsub(), supports substitution of NaNs
# OTHER: {scalar, sequence, Series, DataFrame}
# AXIS: {0, 1, index, columns} -- whether to compare by the index or columns
# FILLVALUE: {None, float} -- fill missing value
@ -225,10 +225,10 @@ pd.DataFrame.rsub(self, other, axis=columns, fill_value=None) # rsub(), support
```py
self * other
pd.Series.mul(self, other, fill_value=None) # mul(), supports substituion of NaNs
pd.Series.rmul(self, other, fill_value=None) # rmul(), supports substituion of NaNs
ps.DataFrame.mul(self, other, axis=columns, fill_value=None) # mul(), supports substituion of NaNs
pd.DataFrame.rmul(self, other, axis=columns, fill_value=None) # rmul(), supports substituion of NaNs
pd.Series.mul(self, other, fill_value=None) # mul(), supports substitution of NaNs
pd.Series.rmul(self, other, fill_value=None) # rmul(), supports substitution of NaNs
ps.DataFrame.mul(self, other, axis=columns, fill_value=None) # mul(), supports substitution of NaNs
pd.DataFrame.rmul(self, other, axis=columns, fill_value=None) # rmul(), supports substitution of NaNs
# OTHER: {scalar, sequence, Series, DataFrame}
# AXIS: {0, 1, index, columns} -- whether to compare by the index or columns
# FILLVALUE: {None, float} -- fill missing value
@ -238,14 +238,14 @@ pd.DataFrame.rmul(self, other, axis=columns, fill_value=None) # rmul(), support
```py
self / other
pd.Series.div(self, other, fill_value=None) # div(), supports substituion of NaNs
pd.Series.rdiv(self, other, fill_value=None) # rdiv(), supports substituion of NaNs
pd.Series.truediv(self, other, fill_value=None) # truediv(), supports substituion of NaNs
pd.Series.rtruediv(self, other, fill_value=None) # rtruediv(), supports substituion of NaNs
ps.DataFrame.div(self, other, axis=columns, fill_value=None) # div(), supports substituion of NaNs
pd.DataFrame.rdiv(self, other, axis=columns, fill_value=None) # rdiv(), supports substituion of NaNs
ps.DataFrame.truediv(self, other, axis=columns, fill_value=None) # truediv(), supports substituion of NaNs
pd.DataFrame.rtruediv(self, other, axis=columns, fill_value=None) # rtruediv(), supports substituion of NaNs
pd.Series.div(self, other, fill_value=None) # div(), supports substitution of NaNs
pd.Series.rdiv(self, other, fill_value=None) # rdiv(), supports substitution of NaNs
pd.Series.truediv(self, other, fill_value=None) # truediv(), supports substitution of NaNs
pd.Series.rtruediv(self, other, fill_value=None) # rtruediv(), supports substitution of NaNs
ps.DataFrame.div(self, other, axis=columns, fill_value=None) # div(), supports substitution of NaNs
pd.DataFrame.rdiv(self, other, axis=columns, fill_value=None) # rdiv(), supports substitution of NaNs
ps.DataFrame.truediv(self, other, axis=columns, fill_value=None) # truediv(), supports substitution of NaNs
pd.DataFrame.rtruediv(self, other, axis=columns, fill_value=None) # rtruediv(), supports substitution of NaNs
# OTHER: {scalar, sequence, Series, DataFrame}
# AXIS: {0, 1, index, columns} -- whether to compare by the index or columns
# FILLVALUE: {None, float} -- fill missing value
@ -255,10 +255,10 @@ pd.DataFrame.rtruediv(self, other, axis=columns, fill_value=None) # rtruediv(),
```py
self // other
pd.Series.floordiv(self, other, fill_value=None) # floordiv(), supports substituion of NaNs
pd.Series.rfloordiv(self, other, fill_value=None) # rfloordiv(), supports substituion of NaNs
ps.DataFrame.floordiv(self, other, axis=columns, fill_value=None) # floordiv(), supports substituion of NaNs
pd.DataFrame.rfloordiv(self, other, axis=columns, fill_value=None) # rfloordiv(), supports substituion of NaNs
pd.Series.floordiv(self, other, fill_value=None) # floordiv(), supports substitution of NaNs
pd.Series.rfloordiv(self, other, fill_value=None) # rfloordiv(), supports substitution of NaNs
ps.DataFrame.floordiv(self, other, axis=columns, fill_value=None) # floordiv(), supports substitution of NaNs
pd.DataFrame.rfloordiv(self, other, axis=columns, fill_value=None) # rfloordiv(), supports substitution of NaNs
# OTHER: {scalar, sequence, Series, DataFrame}
# AXIS: {0, 1, index, columns} -- whether to compare by the index or columns
# FILLVALUE: {None, float} -- fill missing value
@ -268,10 +268,10 @@ pd.DataFrame.rfloordiv(self, other, axis=columns, fill_value=None) # rfloordiv(
```py
self % other
pd.Series.mod(self, other, fill_value=None) # mod(), supports substituion of NaNs
pd.Series.rmod(self, other, fill_value=None) # rmod(), supports substituion of NaNs
ps.DataFrame.mod(self, other, axis=columns, fill_value=None) # mod(), supports substituion of NaNs
pd.DataFrame.rmod(self, other, axis=columns, fill_value=None) # rmod(), supports substituion of NaNs
pd.Series.mod(self, other, fill_value=None) # mod(), supports substitution of NaNs
pd.Series.rmod(self, other, fill_value=None) # rmod(), supports substitution of NaNs
ps.DataFrame.mod(self, other, axis=columns, fill_value=None) # mod(), supports substitution of NaNs
pd.DataFrame.rmod(self, other, axis=columns, fill_value=None) # rmod(), supports substitution of NaNs
# OTHER: {scalar, sequence, Series, DataFrame}
# AXIS: {0, 1, index, columns} -- whether to compare by the index or columns
# FILLVALUE: {None, float} -- fill missing value
@ -281,10 +281,10 @@ pd.DataFrame.rmod(self, other, axis=columns, fill_value=None) # rmod(), support
```py
other ** self
pd.Series.pow(self, other, fill_value=None) # pow(), supports substituion of NaNs
pd.Series.rpow(self, other, fill_value=None) # rpow(), supports substituion of NaNs
ps.DataFrame.pow(self, other, axis=columns, fill_value=None) # pow(), supports substituion of NaNs
pd.DataFrame.rpow(self, other, axis=columns, fill_value=None) # rpow(), supports substituion of NaNs
pd.Series.pow(self, other, fill_value=None) # pow(), supports substitution of NaNs
pd.Series.rpow(self, other, fill_value=None) # rpow(), supports substitution of NaNs
ps.DataFrame.pow(self, other, axis=columns, fill_value=None) # pow(), supports substitution of NaNs
pd.DataFrame.rpow(self, other, axis=columns, fill_value=None) # rpow(), supports substitution of NaNs
# OTHER: {scalar, sequence, Series, DataFrame}
# AXIS: {0, 1, index, columns} -- whether to compare by the index or columns
# FILLVALUE: {None, float} -- fill missing value
@ -299,7 +299,7 @@ NumPy ufuncs work fine with pandas objects.
```py
pd.DataFrame.applymap(self, func) # apply function element-wise
pd.DataFrame.apply(self, func, axis=0, args=()) # apllay a function along an axis of a DataFrame
pd.DataFrame.apply(self, func, axis=0, args=()) # apply a function along an axis of a DataFrame
# FUNC: {function} -- function to apply
# AXIS: {O, 1, index, columns} -- axis along which the function is applied
# ARGS: {tuple} -- positional arguments to pass to func in addition to the array/series
@ -309,7 +309,7 @@ pd.Series.sort_values(self, ascending=True, **kwargs) # sort series by the valu
# ASCENDING: {bool} -- if True, sort values in ascending order, otherwise descending -- DEFAULT True
# INPALCE: {bool} -- if True, perform operation in-place
# KIND: {quicksort, mergesort, heapsort} -- sorting algorithm
# NA_POSITION {first, last} -- ‘first’ puts NaNs at the beginning, ‘last’ puts NaNs at the end
# NA_POSITION {first, last} -- 'first' puts NaNs at the beginning, 'last' puts NaNs at the end
pd.DataFrame.sort_index(self, axis=0, ascending=True, **kwargs) # sort object by labels along an axis
pd.DataFrame.sort_values(self, axis=0, ascending=True, **kwargs) # sort object by values along an axis
@ -317,7 +317,7 @@ pd.DataFrame.sort_values(self, axis=0, ascending=True, **kwargs) # sort object
# ASCENDING: {bool} -- if True, sort values in ascending order, otherwise descending -- DEFAULT True
# INPALCE: {bool} -- if True, perform operation in-place
# KIND: {quicksort, mergesort, heapsort} -- sorting algorithm
# NA_POSITION {first, last} -- ‘first’ puts NaNs at the beginning, ‘last’ puts NaNs at the end
# NA_POSITION {first, last} -- 'first' puts NaNs at the beginning, 'last' puts NaNs at the end
```
## DESCRIPTIVE AND SUMMARY STATISTICS
@ -332,7 +332,7 @@ pd.DataFrame.count(self, numeric_only=False) # count non-NA cells for each colu
### DESCRIBE
Generate descriptive statistics summarizing central tendency, dispersion and shape of dataset’s distribution (exclude NaN).
Generate descriptive statistics summarizing central tendency, dispersion and shape of dataset's distribution (exclude NaN).
```py
pd.Series.describe(self, percentiles=None, include=None, exclude=None)
@ -350,7 +350,7 @@ pd.Series.min(self, skipna=None, numeric_only=None) # minimum of the values for
pd.DataFrame.max(self, axis=None, skipna=None, numeric_only=None) # maximum of the values for the requested axis
pd.DataFrame.min(self, axis=None, skipna=None, numeric_only=None) # minimum of the values for the requested axis
# SKIPNA: {bool} -- exclude NA/null values when computing the result
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not immplemented for Series
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not implemented for Series
```
### IDXMAX - IDXMIN
@ -381,7 +381,7 @@ pd.Series.sum(self, skipna=None, numeric_only=None, min_count=0) # sum of the v
pd.DataFrame.sum(self, axis=None, skipna=None, numeric_only=None, min_count=0) # sum of the values for the requested axis
# AXIS: {0, 1, index, columns} -- axis for the function to be applied on
# SKIPNA: {bool} -- exclude NA/null values when computing the result
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not immplemented for Series
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not implemented for Series
# MIN_COUNT: {int} -- required number of valid values to perform the operation. if fewer than min_count non-NA values are present the result will be NA
```
@ -392,7 +392,7 @@ pd.Series.mean(self, skipna=None, numeric_only=None) # mean of the values
pd.DataFrame.mean(self, axis=None, skipna=None, numeric_only=None) # mean of the values for the requested axis
# AXIS: {0, 1, index, columns} -- axis for the function to be applied on
# SKIPNA: {bool} -- exclude NA/null values when computing the result
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not immplemented for Series
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not implemented for Series
```
### MEDIAN
@ -402,7 +402,7 @@ pd.Series.median(self, skipna=None, numeric_only=None) # median of the values
pd.DataFrame.median(self, axis=None, skipna=None, numeric_only=None) # median of the values for the requested axis
# AXIS: {0, 1, index, columns} -- axis for the function to be applied on
# SKIPNA: {bool} -- exclude NA/null values when computing the result
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not immplemented for Series
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not implemented for Series
```
### MAD (mean absolute deviation)
@ -422,7 +422,7 @@ pd.DataFrame.var(self, axis=None, skipna=None, ddof=1, numeric_only=None) # un
# AXIS: {0, 1, index, columns} -- axis for the function to be applied on
# SKIPNA: {bool} -- exclude NA/null values. if an entire row/column is NA, the result will be NA
# DDOF: {int} -- Delta Degrees of Freedom. divisor used in calculations is N - ddof (N represents the number of elements) -- DEFAULT 1
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not immplemented for Series
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not implemented for Series
```
### STD (standard deviation)
@ -433,7 +433,7 @@ pd.Dataframe.std(self, axis=None, skipna=None, ddof=1, numeric_only=None) # sam
# AXIS: {0, 1, index, columns} -- axis for the function to be applied on
# SKIPNA: {bool} -- exclude NA/null values. if an entire row/column is NA, the result will be NA
# DDOF: {int} -- Delta Degrees of Freedom. divisor used in calculations is N - ddof (N represents the number of elements) -- DEFAULT 1
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not immplemented for Series
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not implemented for Series
```
### SKEW
@ -443,19 +443,19 @@ pd.Series.skew(self, skipna=None, numeric_only=None) # unbiased skew Normalized
pd.DataFrame.skew(self, axis=None, skipna=None, numeric_only=None) # unbiased skew over requested axis Normalized by N-1
# AXIS: {0, 1, index, columns} -- axis for the function to be applied on
# SKIPNA: {bool} -- exclude NA/null values when computing the result
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not immplemented for Series
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not implemented for Series
```
### KURT
Unbiased kurtosis over requested axis using Fisher’s definition of kurtosis (kurtosis of normal == 0.0). Normalized by N-1.
Unbiased kurtosis over requested axis using Fisher's definition of kurtosis (kurtosis of normal == 0.0). Normalized by N-1.
```py
pd.Series.kurt(self, skipna=None, numeric_only=None)
pd.Dataframe.kurt(self, axis=None, skipna=None, numeric_only=None)
# AXIS: {0, 1, index, columns} -- axis for the function to be applied on
# SKIPNA: {bool} -- exclude NA/null values when computing the result
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not immplemented for Series
# NUMERIC_ONLY: {bool} -- include only float, int, boolean columns, not implemented for Series
```
### CUMSUM (cumulative sum)
@ -471,7 +471,7 @@ pd.Dataframe.cumsum(self, axis=None, skipna=True) # cumulative sum over request
```py
pd.Series.cummax(self, skipna=True) # cumulative maximum
pd.Series.cummin(self, skipna=True) # cumulative minimumm
pd.Series.cummin(self, skipna=True) # cumulative minimum
pd.Dataframe.cummax(self, axis=None, skipna=True) # cumulative maximum over requested axis
pd.Dataframe.cummin(self, axis=None, skipna=True) # cumulative minimum over requested axis
# AXIS: {0, 1, index, columns} -- axis for the function to be applied on
@ -499,7 +499,7 @@ pd.DataFrame.diff(self, periods=1, axis=0)
# AXIS: {0, 1, index, columns} -- Take difference over rows or columns
```
### PCT_CAHNGE
### PCT_CHANGE
Percentage change between the current and a prior element.
@ -541,7 +541,7 @@ pd.DataFrame.fillna(self, value=None, method=None, axis=None, inplace=False, lim
## HIERARCHICAL INDEXING (MultiIndex)
Enables storing and manupulation of data with an arbitrary number of dimensions.
Enables storing and manipulation of data with an arbitrary number of dimensions.
In lower dimensional data structures like Series (1d) and DataFrame (2d).
### MULTIIINDEX CREATION
@ -565,7 +565,7 @@ pd.MultiIndex.get_level_values(self, level)
### PARTIAL AND CROSS-SECTION SELECTION
Partial selection “drops” levels of the hierarchical index in the result in a completely analogous way to selecting a column in a regular DataFrame.
Partial selection "drops" levels of the hierarchical index in the result in a completely analogous way to selecting a column in a regular DataFrame.
```py
pd.Series.xs(self, key, axis=0, level=None, drop_level=True) # cross-section from Series
@ -608,7 +608,7 @@ pd.MultiIndex.sortlevel(self, level=0, ascending=True, sort_remaining=True) # s
pd.read_fwf(filepath, colspecs='infer', widths=None, infer_nrows=100) # read a table of fixed-width formatted lines into DataFrame
# FILEPATH: {str, path object} -- any valid string path is acceptable, could be a URL. Valid URLs: http, ftp, s3, and file
# COLSPECS: {list of tuple (int, int), 'infer'} -- list of tuples giving extents of fixed-width fields of each line as half-open intervals { [from, to) }
# WIDTHS: {list of int} -- list of field widths which can be used instead of ‘colspecs’ if intervals are contiguous
# WIDTHS: {list of int} -- list of field widths which can be used instead of "colspecs" if intervals are contiguous
# INFER_ROWS: {int} -- number of rows to consider when letting parser determine colspecs -- DEFAULT 100
pd.read_excel() # read an Excel file into a pandas DataFrame
@ -635,7 +635,7 @@ pd.DataFrame.to_csv(self, path_or_buf, sep=',', na_rep='', columns=None, header=
# COLUMNS: {sequence} -- colums to write
# HEADER: {bool, list of str} -- write out column names. if list of strings is given its assumed to be aliases for column names
# INDEX: {bool, list of str} -- write out row names (index)
# ENCODING: {str} -- string representing encoding to use -- DEFAULT ‘utf-8’
# ENCODING: {str} -- string representing encoding to use -- DEFAULT "utf-8"
# LINE_TERMINATOR: {str} -- newline character or character sequence to use in the output file -- DEFAULT os.linesep
# DECIMAL: {str} -- character recognized as decimal separator (in EU ,)

30
Python/Libs/Math/seaborn.md
View file

@ -17,18 +17,18 @@ sns.set(style='darkgrid')
```python
sns.replot(x='name_in_data', y='name_in_data', hue='point_color', size='point_size', style='point_shape', data=data)
# HUE, SIZE and STYLE: {name in data} -- used to differenciate points, a sort-of 3rd dimention
# HUE, SIZE and STYLE: {name in data} -- used to differentiate points, a sort-of 3rd dimension
# hue behaves differently if the data is categorical or numerical, numerical uses a color gradient
# SORT: {False, True} -- avoid sorting data in function of x
# CI: {None, sd} -- avoid comuting confidence intervals or plot standard deviation
# CI: {None, sd} -- avoid computing confidence intervals or plot standard deviation
# (aggregate multiple measurements at each x value by plotting the mean and the 95% confidence interval around the mean)
# ESTIMATOR: {None} -- turn off aggregation of multiple observations
# MARKERS: {True, False} -- evidetiate observations with dots
# DASHES: {True, False} -- evidetiate observations with dashes
# MARKERS: {True, False} -- evidenziate observations with dots
# DASHES: {True, False} -- evidenziate observations with dashes
# COL, ROW: {name in data} -- categorical variables that will determine the grid of plots
# COL_WRAP: {int} -- “Wrap” the column variable at this width, so that the column facets span multiple rows. Incompatible with a row facet.
# COL_WRAP: {int} -- "Wrap" the column variable at this width, so that the column facets span multiple rows. Incompatible with a row facet.
# SCATTERPLOT
# depicts the joint distibution of two variables usinga a cloud of points
# depicts the joint distribution of two variables using a cloud of points
# kind can be omitted since scatterplot is the default for replot
sns.replot(kind='scatter') # calls scatterplot()
sns.scatterplot() # underlying axis-level function of replot()
@ -45,16 +45,16 @@ sns.lineplot() # underlying axis-level function of replot()
## CATPLOT (categorical)
Categorical: dicided into discrete groups.
Categorical: divided into discrete groups.
```python
sns.catplot(x='name_in_data', y='name_in_data', data=data)
# HUE: {name in data} -- used to differenciate points, a sort-of 3rd dimention
# HUE: {name in data} -- used to differenziate points, a sort-of 3rd dimension
# COL, ROW: {name in data} -- categorical variables that will determine the grid of plots
# COL_WRAP: {int} -- “Wrap” the column variable at this width, so that the column facets span multiple rows. Incompatible with a row facet.
# ORDER, HUE_ORDER: {list of strings} -- oreder of categorical levels of the plot
# COL_WRAP: {int} -- "Wrap" the column variable at this width, so that the column facets span multiple rows. Incompatible with a row facet.
# ORDER, HUE_ORDER: {list of strings} -- order of categorical levels of the plot
# ROW_ORDER, COL_ORDER: {list of strings} -- order to organize the rows and/or columns of the grid in
# ORIENT: {'v', 'h'} -- Orientation of the plot (can also swap x&y assignement)
# ORIENT: {'v', 'h'} -- Orientation of the plot (can also swap x&y assignment)
# COLOR: {matplotlib color} -- Color for all of the elements, or seed for a gradient palette
# CATEGORICAL SCATTERPLOT - STRIPPLOT
# adjust the positions of points on the categorical axis with a small amount of random “jitter”
@ -85,7 +85,7 @@ sns.boxplot()
Combines a boxplot with the kernel density estimation procedure.
```py
sns.catplot(kind='violon')
sns.catplot(kind='violin')
sns.violonplot()
```
@ -113,7 +113,7 @@ sns.pointplot()
# JOIN: {bool} -- if True, lines will be drawn between point estimates at the same hue level
# SCALE: {float} -- scale factor for the plot elements
# ERRWIDTH: {float} -- thickness of error bar lines (and caps)
# CAPSIZE: {float} -- width of the “caps” on error bars
# CAPSIZE: {float} -- width of the "caps" on error bars
```
### CATEGORICAL ESTIMATE - BARPLOT
@ -126,7 +126,7 @@ sns.barplot()
# CI: {float, sd} -- size of confidence intervals to draw around estimated values, sd -> standard deviation
# ERRCOLOR: {matplotlib color} -- color for the lines that represent the confidence interval
# ERRWIDTH: {float} -- thickness of error bar lines (and caps)
# CAPSIZE: {float} -- width of the “caps” on error bars
# CAPSIZE: {float} -- width of the "caps" on error bars
# DODGE: {bool} -- whether elements should be shifted along the categorical axis if hue is used
```
@ -173,7 +173,7 @@ sns.rugplot(a=data) # -> axes obj with plot on it
Fit and plot a univariate or bivariate kernel density estimate.
```py
# DATA: {1D array-like} -- inpoy data
# DATA: {1D array-like} -- input data
sns.kdeplot(data=data)
# DATA2 {1D array-like} -- second input data. if present, a bivariate KDE will be estimated.
# SHADE: {bool} -- if True, shade-in the area under KDE curve (or draw with filled contours is bivariate)

28
Python/Libs/Web/BeautifulSoup.md
View file

@ -8,7 +8,7 @@ from bs4 import BeautifulSoup
import requests
import lxml # better html parser than built-in
response = requests.get("url") # retuire a web page
response = requests.get("url") # retrieve a web page
soup = BeautifulSoup(response.text, "html.parser") # parse HTML from response w/ python default HTML parser
soup = BeautifulSoup(response.text, "lxml") # parse HTML from response w/ lxml parser
@ -32,7 +32,7 @@ type(tag) # <class 'bs4.element.Tag'>
print(tag) # <b class="boldest">Extremely bold</b>
tag.name # tag name
tag["attribute"] # access to ttag attribute values
tag["attribute"] # access to tag attribute values
tag.attrs # dict of attribue-value pairs
```
@ -48,21 +48,21 @@ A string corresponds to a bit of text within a tag. Beautiful Soup uses the `Nav
soup.<tag>.<child_tag> # navigate using tag names
<tag>.contents # direct children as a list
<tag>.children # direct children as a genrator for iteration
<tag>.descendats # iterator over all childered, recusive
<tag>.children # direct children as a generator for iteration
<tag>.descendants # iterator over all children, recursive
<tag>.string # tag contents, does not have further children
# If a tag’s only child is another tag, and that tag has a .string, then the parenttag is considered to have the same .string as its child
# If a tag contains more than one thing, then it’s not clear what .string should refer to, so .string is defined to be None
# If a tag's only child is another tag, and that tag has a .string, then the parent tag is considered to have the same .string as its child
# If a tag contains more than one thing, then it's not clear what .string should refer to, so .string is defined to be None
<tag>.strings # generattor to iterate over all children's strings (will list white space)
<tag>.stripped_strings # generattor to iterate over all children's strings (will NOT list white space)
<tag>.strings # generator to iterate over all children's strings (will list white space)
<tag>.stripped_strings # generator to iterate over all children's strings (will NOT list white space)
```
### Going Up
```py
<tag>.parent # tags direct parent (BeautifleSoup has parent None, html has parent BeautifulSoup)
<tag>.parent # tags direct parent (BeautifulSoup has parent None, html has parent BeautifulSoup)
<tag>.parents # iterable over all parents
```
@ -94,7 +94,7 @@ soup.<tag>.<child_tag> # navigate using tag names
soup.find_all("tag") # by name
soup.find_all(["tag1", "tag2"]) # multiple tags in a list
soup.find_all(function) # based on a bool function
sopu.find_all(True) # Match everyting
soup.find_all(True) # Match everything
```
## Methods
@ -102,10 +102,10 @@ sopu.find_all(True) # Match everyting
Methods arguments:
- `name` (string): tag to search for
- `attrs` (dict): attributte-value pai to search for
- `attrs` (dict): attribute-value pai to search for
- `string` (string): search by string contents rather than by tag
- `limit` (int). limit number of results
- `**kwargs`: be turned into a filter on one of a tag’s attributes.
- `**kwargs`: be turned into a filter on one of a tag's attributes.
```py
find_all(name, attrs, recursive, string, limit, **kwargs) # several results
@ -140,7 +140,7 @@ soup.select("css_selector") # search for CSS selectors of HTML tags
<tag>["attribute"] = "value" # modify the attribute value
del <tag>["attribute"] # remove the attribute
soup.new_tag("name", <attribute> = "value") # creat a new tag with specified name and attributes
soup.new_tag("name", <attribute> = "value") # create a new tag with specified name and attributes
<tag>.string = "new content" # modify tag text content
<tag>.append(item) # append to Tag content
@ -161,7 +161,7 @@ soup.new_tag("name", <attribute> = "value") # creat a new tag with specified na
<tag>.replace_with(item) # remove a tag or string from the tree, and replaces it with the tag or string of choice
<tag>.wrap(other_tag) # wrap an element in the tag you specify, return the new wrapper
<tag>.unwrap() # replace a tag with whatever’s inside, good for stripping out markup
<tag>.unwrap() # replace a tag with whatever's inside, good for stripping out markup
<tag>.smooth() # clean up the parse tree by consolidating adjacent strings
```

6
Python/Libs/Web/Flask/Flask.md
View file

@ -34,14 +34,14 @@ Converter Type | Accepts
`uuid` | UUID strings
```python
@app.route("/user/<string:username>") # hanle URL at runtime
@app.route("/user/<string:username>") # handle URL at runtime
def profile(username):
return f"{escape(username)}'s profile'"
```
## Redirection
`url_for(endpoint, **values)` is used to redirect passing keyeworderd arguments. It can be used in combination with `@app.route("/<value>")` to accept the paassed arguments.
`url_for(endpoint, **values)` is used to redirect passing keyworded arguments. It can be used in combination with `@app.route("/<value>")` to accept the passed arguments.
```py
from flask import Flask, redirect, url_for
@ -137,7 +137,7 @@ In `parent_template.html`:
The content of the block will be filled by the child class.
In `child_template.hmtl`:
In `child_template.html`:
```html
{% extends "parent_template.html" %}

2
Python/Libs/Web/Flask/requests.md
View file

@ -27,7 +27,7 @@ In `login.html`:
```html
<html>
<!-- action="#" goes to page itsef but with # at the end of the URL -->
<!-- action="#" goes to page itself but with # at the end of the URL -->
<form action="#" method="post">
<input type="text" name="field name">
</html>

8
Python/Libs/Web/requests.md
View file

@ -21,7 +21,7 @@ The response message consists of:
```text
1xx -> INFORMATIONAL RESPONSE
2xx -> SUCCESS
200 OK -> request succesful
200 OK -> request successful
3xx -> REDIRECTION
4xx -> CLIENT ERRORS
404 NOT FOUND -> resource not found
@ -85,7 +85,7 @@ requests.post('URL', json={'key': 'value'})
### INSPECTING THE REQUEST
```py
# requests lib prepares the requests nefore sending it
# requests lib prepares the requests before sending it
response = requests.post('URL', data={'key':'value'})
response.request.something # inspect request field
```
@ -93,7 +93,7 @@ response.request.something # inspect request field
## AUTHENTICATION
```py
requests.get('URL', auth=('uesrname', 'password')) # use implicit HTTP Basic Authorization
requests.get('URL', auth=('username', 'password')) # use implicit HTTP Basic Authorization
# explicit HTTP Basic Authorization and other
from requests.auth import HTTPBasicAuth, HTTPDigestAuth, HTTPProxyAuth
@ -101,7 +101,7 @@ from getpass import getpass
requests.get('URL', auth=HTTPBasicAuth('username', getpass()))
```
### PERSOANLIZED AUTH
### PERSONALIZED AUTH
```py
from requests.auth import AuthBase

194
Python/Python.md
View file

@ -21,12 +21,12 @@ dir(object) # return an alphabetized list of names comprising (some of) the att
import sys # importa modulo
from sys import argv # importa singolo elemento da un modulo
from sys import * # importa tutti gli elementi di un modulo (non cecessaria sintassi modulo.metodo)
from sys import * # importa tutti gli elementi di un modulo (non necessaria sintassi modulo.metodo)
import sys as alias # importa il modulo con un alias, utilizzo alias.metodo
# SET CARATTERI
import string
string.ascii_lowecase = 'abcdefghijklmnopqrstuvwxyz'
string.ascii_lowercase = 'abcdefghijklmnopqrstuvwxyz'
string.asci_uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
string.asci_letters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
string.digits = '0123456789'
@ -43,14 +43,14 @@ string.whitespace
```py
"""istruzioni a dx di = eseguite prima di istruzioni a sx di ="""
variabile = espressione # il tipo della variabile viene deciso dianmicamente da python in base al contenuto
variabile = espressione # il tipo della variabile viene deciso dinamicamente da python in base al contenuto
var_1, var_2 = valore1, valore2 # assegnamento parallelo
var_1, var_2 = var_2, var_1 # swap valori
# conditional assignement
# conditional assignment
x = a if condition else b
x = a or b # If bool(a) returns False, then x is assigned the value of b
# a series of OR expressions has the effect of returning the first item that evaluates True, or the last item (last item sould be a literal).
# a series of OR expressions has the effect of returning the first item that evaluates True, or the last item (last item should be a literal).
```
### Conversione Tipo Variabile
@ -60,7 +60,7 @@ x = a or b # If bool(a) returns False, then x is assigned the value of b
### Assegnamento Espressioni
```py
(var := expressione) # assegna ad una variabile un espressione per evitare di ripetere l'espressione
(var := expression) # assegna ad una variabile un espressione per evitare di ripetere l'espressione
```
### Confronto Variabili (`==` vs `is`)
@ -88,19 +88,19 @@ print(f'{name=}, {marks=}') # OUTPUT: name=Alex, marks=94.5
# USO DEI PLACEHOLDER
print('Name is %s, Marks are %3.2f' % (name, marks)) # metodo ereditato da C. La variabile viene sostituita al posto di %..
print("Name is {}, Marks are {}".format(name, marks))
print("Name is {1}, Marks are {2}".format(marks, name)) # indici in parentesi odrinano elementi in .format
print("Name is {n}, Marks are {m}".format(m = '94.5', n = 'Alex')) # indici in parentesi odrinano elementi in .format
print("Name is {1}, Marks are {2}".format(marks, name)) # indici in parentesi ordinano elementi in .format
print("Name is {n}, Marks are {m}".format(m = '94.5', n = 'Alex')) # indici in parentesi ordinano elementi in .format
print(f'Name is {name}, Marks are {marks}') # formattazione con f-strings
```
### Format Specification Mini-Language
`{value:width.precision symbol}`
`width.precision` => numeroCifreTottali.numeroCifreDecimali
`width.precision` => numeroCifreTotali.numeroCifreDecimali
Format: `[[fill]align] [sign] [#] [width] [grouping] [.precidion] [type]`
Format: `[[fill]align] [sign] [#] [width] [grouping] [.precision] [type]`
OVVERRIDE __format__()
OVERRIDE __format__()
{!a} | chiama ascii() sulla variabile
{!r} | chiama repr() sulla variabile
{!s} | chiama str() sulla variabile
@ -108,10 +108,10 @@ OVVERRIDE __format__()
RIEMPIMENTO [fill]
{<qualsiasi_carattere>}
| `[align]` | Allinemanto |
| `[align]` | Allineamento |
| --------- | ---------------------- |
| `:<` | allinemaneto sininstra |
| `:>` | allinemento destra |
| `:<` | allineamento sinistra |
| `:>` | allineamento destra |
| `:=` | padding dopo il segno |
| `:^` | centrato |
@ -139,14 +139,14 @@ RIEMPIMENTO [fill]
| `:e` | output è notazione esponenziale (precisione base 6 cifre) |
| `:E` | output è notazione esponenziale (precisione base 6 cifre) separatore maiuscolo |
| `:f` | output è float (precisione base 6 cifre) |
| `:%` | output è percentuale (moltiplica * 100, diplay come :f) |
| `:%` | output è percentuale (moltiplica * 100, display come :f) |
### Input Da Tastiera
```py
# input ritorna sempre una STRINGA
s = input() # richiesta input senza messaggio
s = input('Prompt') # richiesta imput
s = input('Prompt') # richiesta input
i = int(input('prompt')) # richiesta input con conversione di tipo
# INPUT MULTIPLI
@ -158,7 +158,7 @@ lista = [int(x) for x in input('prompt').split('separatore')]
```py
a = 77
b = 1_000_000 # underscore può essere usato per seoarare gruppi di cifre
b = 1_000_000 # underscore può essere usato per separare gruppi di cifre
c = -69
# float numbers
@ -184,7 +184,7 @@ bin(3616544)
hex(589)
oct(265846)
# COVERSIONE UNICODE
# CONVERSIONE UNICODE
ord(c) # Given a string representing one Unicode character, return an integer representing the Unicode code point of that character
chr(i) # Return the string representing a character whose Unicode code point is the integer i
@ -196,21 +196,21 @@ round(num, precisione) # arrotonda il numero alla data precisione, non converte
### Confronto Numeri Decimali
Non usare `==` o `!=` per confrontare numeri in virgola mobile. Essi sono approssiamazioni o hanno parecchie cifre.
Non usare `==` o `!=` per confrontare numeri in virgola mobile. Essi sono approssimazioni o hanno parecchie cifre.
Conviene verificare se la differenza tra i numeri è sufficientemente piccola.
## Stringhe
```py
stringa = 'contenuto stringa' # asegnazione e creazione variabile stringa
stringa = 'contenuto stringa' # assegnazione e creazione variabile stringa
stringa = '''multi
line
string'''
stringa3 = stringa1 + stringa2 # concatenazione stringhe (polimorfismo operatore +)
# INDEXING (selezione di un carattere nella srtinga)
# INDEXING (selezione di un carattere nella stringa)
stringa[0]
stringa[2]
stringa[-3] # selezione partendo dal fondo (indice negativo)
@ -220,7 +220,7 @@ print(stringa * n)
len(stringa) # mostra la lunghezza di una stringa
# SLICING (estrazione di sottostringhe, non include la posizione dell'ultimo indice)
# SLICING (estrazione di sotto-stringhe, non include la posizione dell'ultimo indice)
stringa[0:5]
stringa[:6]
stringa[-3:-1]
@ -257,7 +257,7 @@ stringa.capitalize()
# SEPARAZIONE IN ELEMENTI LISTA
stringa.split()
stringa.split('separatore') # separa usando il separatore (separatore omesso nella lista)
stringa.partition('char') # -> tuple # sepra la stringa i 3 parti alla prima occorrenza di separatore
stringa.partition('char') # -> tuple # separa la stringa i 3 parti alla prima occorrenza di separatore
# METODI IS_CHECK --> bool
stringa.isalnum()
@ -284,18 +284,18 @@ lista = [9, 11, 'WTC', -5.6, True] # le liste possono contenere dati di tipo div
lista[3] # indexing
lista[3:5] # slicing
lista * 3 # repetition
len(lista) # lenght
len(lista) # length
lista3 = lista1 + lista2 # concatenazione liste (polimorfismo operatore +)
lista[indice] = valore # modifica elemento lista
del(lista[1]) # rimozione per indice (INBUILT IN PYTHON)
# modifica la lista tra gli indici start e stop riasegnando gli elementi dell'iterabile
# modifica la lista tra gli indici start e stop riassegnando gli elementi dell'iterabile
lista[start:stop] = iterabile
# METODI LISTE
lista.append(oggetto) # aggiunge oggetto al fondo
lista.count(item) # conta il numero di occorrenze di item
lista.extend(sequenza) # aggiunge gli elementi di sequenza alla lista
lista.insert(posizione, oggetto) # inserise oggetto in lista[posizione]
lista.insert(posizione, oggetto) # inserisce oggetto in lista[posizione]
lista.index(item) # restituisce l'indice di item
lista.remove(item) # rimuove item
lista.pop(item) # elimina item e lo restituisce
@ -354,7 +354,7 @@ var = [(exp_1, exp_2) for item_1 in seq_1 for item_2 in seq_2] # --> [(..., ...
```py
# LE TUPLE NON POSSONO ESSERE MODIFICATE
tuple = (69, 420, 69, 'abc') # assegnazione tuple
tuple = (44, ) # tuple di signolo elemento necessitano di una virgola
tuple = (44, ) # tuple di singolo elemento necessitano di una virgola
tuple[3] # indexing
tuple * 3 # repetition
@ -376,7 +376,7 @@ var_1, (var_2, var_3) = tup
#OPERATORE *VAR (tuple unpacking)
var_1, var_2, *rest = sequenza # var_1 = seq[0], var_2 = seq[1], rest = seq[2:]
var_1, *body, var_2, var_3 = sequeza # var_1 = seq[0], body = seq[1:-2], var_2 = sequenza[-2], var_3 = seq[-1]
var_1, *body, var_2, var_3 = sequenza # var_1 = seq[0], body = seq[1:-2], var_2 = sequenza[-2], var_3 = seq[-1]
# *var recupera gli item in eccesso, se in assegnamento parallelo usabile max una volta ma in posizione qualsiasi
```
@ -411,14 +411,14 @@ set.remove(item) # rimuove item dal set se presente, altrimenti solleva KeyErro
set.discard(item) #rimuove item dal set se presente, altrimenti fa nulla
set.difference(*sets) # -> set # restituisce elementi in set che sono assenti in *sets
set.difference_update(*sets) # rimuove le differenze dal set_2
set.union(*sets) # -> set # restituisce tutti gli elemnti dei set
set.union(*sets) # -> set # restituisce tutti gli elementi dei set
set.update(*sets) # aggiunge elementi *sets a set
set.intersection(*sets) # -> set # restituisce gli elementi comuni ai set
set.intersection_update(*sets) # rimuove tutti gli elementi tranne quelli comuni ai set
set.symmetric_difference(*sets) # -> set # restituisce gli elementi non comuni ai set
set.symmetric_difference_update(*sets) # rimuove tutti gli elementi comuni ai set (lasci solo gli elementi non comuni)
set_1.isdisjoint(set_2) # -> bool # True se non ci sono elementi comunni (intersezione è vuota)
set_1.isdisjoint(set_2) # -> bool # True se non ci sono elementi comuni (intersezione è vuota)
set_1.issubset(set_2) # -> bool # True se ogni elemento di set_1 è anche in set_2
set_1.issuperset(set_2) # -> bool # True se ogni elemento di set_2 è anche in set_1
@ -461,7 +461,7 @@ bytearray.count(subseq, start, end) # restituisce conteggio apparizioni subseq
BYTE LITERALS
ASCII --> stesso carattere
tab, newline, carriage return, escape sequence --> \t, \n, \r, \\
altro --> escape sequence exadeciamle (null byte --> \x00)
altro --> escape sequence esadecimale (null byte --> \x00)
Unicode Literals:
@ -485,11 +485,11 @@ stringa.encode('utf-8', errors='replace') # -> b'byte literals'
# DECODING
# trasforma byte literal in stringa
# error='replace' sostituisce gli errori (byte literal non appartenentia formato di decodifica) con U+FFFD "REPLACEMENT CHARARCTER"
# error='replace' sostituisce gli errori (byte literal non appartenenti a formato di decodifica) con U+FFFD "REPLACEMENT CHARACTER"
bytes.decode('utf-8', errors='replace') # -> str
# NORMALIZZAZIONE UNICODE
# gestione equivalenti canconici unicode (e.g. é, e\u0301 sono equivalenti per unicode)
# gestione equivalenti canonici unicode (e.g. é, e\u0301 sono equivalenti per unicode)
import unicodedata
unicodedata.normalize(form, unicode_string) # FORM: NFC,NFD, NFCK, NFDK
# NFC --> "Normalization Form C" --> produce la stringa equivalente più corta
@ -588,9 +588,9 @@ d | e # {'spam': 1, 'eggs': 2, 'cheese': 'cheddar', 'aardvark': 'Ethel'}
e | d # {'aardvark': 'Ethel', 'spam': 1, 'eggs': 2, 'cheese': 3}
d |= e # {'spam': 1, 'eggs': 2, 'cheese': 'cheddar', 'aardvark': 'Ethel'}
# DIZIONARI ANNIDATI (possibile annidare dizioanari all'interno di dizionari)
# DIZIONARI ANNIDATI (possibile annidare dizionari all'interno di dizionari)
my_dict = {'key_1':123, 'key_2':[12, 23, 33], 'key_3':['item_0', 'item_1', 'item_2']}
my_dict['key'][0] # restituisce elemento annnidato
my_dict['key'][0] # restituisce elemento annidato
# DICT COMPREHENSIONS
var = {key : value for elemento in sequenza}
@ -598,7 +598,7 @@ var = {key : value for elemento in sequenza}
## Operators
### Methematical Operators
### Mathematical Operators
| Operator | Operation |
| -------- | ------------------------------ |
@ -621,7 +621,7 @@ var = {key : value for elemento in sequenza}
| x `==` y | equality |
| x `!=` y | inequality |
### Assignement
### Assignment
| Operator | Operation |
| --------- | ---------- |
@ -646,7 +646,7 @@ var = {key : value for elemento in sequenza}
| x `^` y | bitwise XOR |
| x `|` y | bitwise OR |
| x `<<` y | left bit shift |
| x `>>` y | rigth bit shift |
| x `>>` y | right bit shift |
### Logical Operators
@ -667,7 +667,7 @@ var = {key : value for elemento in sequenza}
| Operator | Operation |
| -------- | ---------------------- |
| `in` | item in cooection |
| `in` | item in collection |
| `not in` | item not in collection |
### Precedenza Operatori
@ -691,16 +691,7 @@ built-in objects considered *false*:
- zero of any numeric type: `0`, `0.0`, `0j`, `Decimal(0)`, `Fraction(0, 1)`
- empty sequences and collections: `''`, `()`, `[]`, `{}`, `set()`, `range(0)`
### `if-else` semplice
```py
if (condizione):
# code here
else:
# code here
```
### `if-else` multiramo
### `if-else`
```py
if (condizione):
@ -726,7 +717,7 @@ contextmanager.__enter__(self)
# restituisce exc_type, exc_value, traceback
contextmanager.__exit__(self, exc_type, exc_value, traceback)
# exc_type: exception class
# exc_value: exception istance
# exc_value: exception instance
# traceback: traceback object
# NO EXCEPTION -> restituisce None, None, None
# SOPPRESSIONE ECCEZIONE: necessario restituire valore True
@ -765,7 +756,7 @@ for key, value in dict.items():
### Istruzioni `break` & `continue`
`break`: causa l'uscita immediata dal ciclo senza l'esecuzione delle successive iterazioni
`continue`: salte le restanti istruzioni del'iterazione e prosegue il ciclo
`continue`: salta le restanti istruzioni del'iterazione e prosegue il ciclo
### Istruzione `range`
@ -785,7 +776,7 @@ list(enumerate(iterabile)) # restituisce lista di tuple [(1, iterabile[0]), (2,
```py
list_1 = [1, 2, 3, 4, 5]
lsit_2 = ['a', 'b', 'c', 'd', 'e']
list_2 = ['a', 'b', 'c', 'd', 'e']
zip(list_1, list_2) # restituisce oggetto zip
list(zip(list_1, list_2)) # restituisce lista di tuple fondendo la lista [(list_1[0], list_2[0]), (list_1[1], list_2[1]), ...]
@ -802,12 +793,12 @@ randint(inizio, fine) # restituisce un intero random compreso tra inizio e fine
### Istruzione `in`
```py
item in iterabile # controlla presenza di intem in iterabile (restituisce True o False)
item in iterabile # controlla presenza di item in iterabile (restituisce True o False)
```
## Funzioni
### Definizone Funzione
### Definizione Funzione
```py
def nome_funzione (parametri):
@ -820,14 +811,14 @@ def nome_funzione (parametri):
`nome_funzione(parametri)`
### Specificare Tipo Paremetri In Funzioni
### Specificare Tipo Parametri In Funzioni
- parametri prima di `/` possono essere solo *posizionali*
- parametri tra `/` e `*` possono essere *posizionali* o *keyworded*
- parametri dopo `*` possono essere solo *keyworded*
```py
def funz(a, b, /, c, d, *, e, f):
def func(a, b, /, c, d, *, e, f):
# code here
```
@ -865,17 +856,17 @@ def funzione (parametro1 = valore1, parametro2 = valore3): # valori di default i
# code here
return espressione
funzione(parametro2 = valore2, parametro1 = valore1) # argometi passati con keyword per imporre l'ordine di riferimento
funzione(parametro2 = valore2, parametro1 = valore1) # argomenti passati con keyword per imporre l'ordine di riferimento
```
### VARIABILI GLOBALI E LOCALI
```py
# global scope
def funz_esterna():
def func_esterna():
# enclosing local scope
# code here
def funz_interna():
def func_interna():
# local scope
# code here
```
@ -898,11 +889,11 @@ def funzione():
# code here
```
### Iteratabili, Iteratori E Generatori
### Iterabili, Iteratori E Generatori
**Iterabile**: oggetto implementante `__iter__()`, sequenze e oggetti supportanti `__getitem__` con index `0`
**Iteratore**: oggetto implementante `__next__` e `__iter__` (**protocollo iteratore**), quando interamente consumato da next() diventa inutilizablie.
**Iteratore**: oggetto implementante `__next__` e `__iter__` (**protocollo iteratore**), quando interamente consumato da next() diventa inutilizzabili.
Gli iteratori sono iterabili, viceversa non vero. Restituisce `StopIteration` quando `next()` ha restituito tutti gli elementi.
**Funzione Generatore**: funzione con keyword `yield` (se presente anche `return` causa `StopIteration`), restituisce un generatore che produce i valori uno alla volta.
@ -913,7 +904,7 @@ Funzionamento `iter()`:
- chiama __iter__()
- in assenza di esso python sfrutta __getitem__() (se presente) per creare un iteratore che tenta di recuperare gli item in ordine, partendo dall'indice `0`
- in caso di fallimento resituisce `TypeError "obj_cls is not iterable"`
- in caso di fallimento restituisce `TypeError "obj_cls is not iterable"`
**Note**: `abc.Iterable` non controlla la presenza di `__getitem__` per decidere se un sotto-oggetto è membro conseguentemente il miglior test per l'iterabilità è usare `iter()` e gestirne le eccezioni.
@ -923,7 +914,7 @@ Funzionamento `iter()`:
next(iterabile) # prossimo item dell'iterabile o errore StopIteration
iter(oggetto) # ottiene un iteratore a partire da un oggetto
# chiama callable_onj.next() senza argomenti finche esso restituisce valori diversi da sentinella
# chiama callable_onj.next() senza argomenti finché esso restituisce valori diversi da sentinella
iter(callable_obj, sentinella)
```
@ -948,7 +939,7 @@ for item in custom_generator(parametri):
# solleva eccezione al punto di sospensione e restituisce valore del generatore
# se il generatore termina senza restituire valori solleva StopIteration
# se un eccezione non viene gestita viene propagata al chiamante
generator.throw(ExceptionType, exceptio_value, traceback)
generator.throw(ExceptionType, exception_value, traceback)
# solleva GeneratorExit al punto si sospensione
# se generatore restituisce un valore -> RuntimeError
@ -962,7 +953,7 @@ generator.close()
# sequenza di lunghezza zero (valori generati sul momento)
var = (espressione for iterabile in sequenza if condizione)
# ISTRUZIONE ENUMERATE()
# restituisce una lista di tuple associando ad ogni elemendo della sequenza un indice di posizione
# restituisce una lista di tuple associando ad ogni elemento della sequenza un indice di posizione
# [(0, sequenza[0]), (1, sequenza[1]), (2, sequenza[2]), ...)
enumerate(sequenza) # -> oggetto enumerate
```
@ -1004,7 +995,7 @@ def coroutine(func):
# TERMINAZIONE COROUTINE E EXCEPTION HANDLING
# eccezioni in coroutine non gestite si propagano alle iterazioni successive
# un eccezione causa la tarminazione della coroutine che non puo riprendere
# un eccezione causa la terminazione della coroutine che non puo riprendere
# yield solleva eccezione, se gestita ciclo continua
# throw() restituisce valore del generatore
@ -1019,7 +1010,7 @@ coroutine.close()
### `yield from <iterabile>`
**Note**: auto-priming generators incomplatible with `yield from`
**Note**: auto-priming generators incompatible with `yield from`
**DELEGATING GENERATOR**: funzione generatore contenente yield from
**SUBGENERATOR**: generatore ottenuto da `yield from <iterabile>`
@ -1034,8 +1025,8 @@ La funzione principale di `yield from` è aprire una canale bidirezionale tra il
- Any values that the subgenerator yields are passed directly to the caller of the delegating generator (i.e., the client code).
- Any values sent to the delegating generator using `send()` are passed directly to the subgenerator.
- If the sent value is `None`, the subgenerator’s `__next__()` method is called.
- If the sent value is not `None`, the subgenerator’s `send()` method is called.
- If the sent value is `None`, the subgenerator's `__next__()` method is called.
- If the sent value is not `None`, the subgenerator's `send()` method is called.
- If the call raises `StopIteration`, the delegating generator is resumed.
- Any other exception is propagated to the delegating generator.
@ -1067,7 +1058,7 @@ def delegating_gen(var):
def client():
# code here
result = delegating_gen() # use delegating_gen
result.send(None) # termina istanza sub_gen (IMPORATNTE)
result.send(None) # termina istanza sub_gen (IMPORTANTE)
```
## Ricorsione
@ -1085,9 +1076,6 @@ def factorial(n):
else:
result = (n*factorial(n-1))
return result
num = int(input('Enther a number to calculate it\'s factorial:'))
print(factorial(num))
```
## Funzioni Avanzate
@ -1103,31 +1091,31 @@ def funzione(parametri):
# chiamata funzione senza parentesi
funzione # restituisce oggetto funzione
var = funzione # assegna (per riferimento) la funzione ad una variabile.
# la chiamata funziona anche se la funz originale viene eliminata (del funzione)
# la chiamata funziona anche se la func originale viene eliminata (del funzione)
var() # chiama la funzione tramite la variabile (usando le parentesi tonde)
```
### Funzioni Annidate
```py
# funz_interna locale viene ritornata per riferimento
def funz_esterna(args):
# func_interna locale viene ritornata per riferimento
def func_esterna(args):
def funz_interna(): # funz_interna ha accesso a scope funzione esterna (aka Closure)
def func_interna(): # func_interna ha accesso a scope funzione esterna (aka Closure)
# code here
return funz_interna # restituisce funz_interna
return func_interna # restituisce func_interna
funz_esterna() # chiamata funz_esterna che chiama funz_interna (risultato funz_esterna è riferimento funz_interna)
func_esterna() # chiamata func_esterna che chiama func_interna (risultato func_esterna è riferimento func_interna)
```
### Funzioni Passate Per Argomento
```py
# funzione passata come argomento viene eseguita (chiamata) all'esecuzione della funzione a cui viene passata
def funz_esterna(funzione):
def func_esterna(funzione):
funzione() # chiama funzione passata come argomento
funz_esterna() # esecuzione funz_esterna chiama funz_interna
func_esterna() # esecuzione func_esterna chiama func_interna
```
### Funzioni Incapsulanti Funzioni (Argomenti Wrapper = Argomenti Wrapped)
@ -1138,7 +1126,7 @@ def wrapped(*args):
def wrapper(*args):
# instructions
wrapped(*args) # wrapped chiamata con gli argomeni passati a wrapper AS-IS (args = tupla) senza incapsulamento in una tupla
wrapped(*args) # wrapped chiamata con gli argomenti passati a wrapper AS-IS (args = tuple) senza incapsulamento in una tuple
```
## LAMBDA Functions
@ -1154,28 +1142,28 @@ var(args) # invocazione lambda
## Decoratori
Entita' chiamabile che prende in input una funzione (come argomento).
Entità' chiamabile che prende in input una funzione (come argomento).
Eventualmente effettua operazioni con la funzione decorata e la restituisce o sostituisce.
vengono eseguiti all'importazione, prima di ogni altra istruzione.
```py
# STRUTTURA DECORATORE PARZIALE (SOSTITUISCE FUNZIONE IMPUT)
# STRUTTURA DECORATORE PARZIALE (SOSTITUISCE FUNZIONE INPUT)
def decorator(funzione): # prende in input una funzione
def wrapper(): # funzione decoratrice
# code here
return wrapper # restituisce wrapper (chiamata a funz_decorata chiama wrapper)
return wrapper # restituisce wrapper (chiamata a func_decorata chiama wrapper)
# STRUTTURA DECORATORE COMPLETA (MODOFICA FUNZIONE INPUT)
# STRUTTURA DECORATORE COMPLETA (MODIFICA FUNZIONE INPUT)
def decorator(funzione): # prende in input una funzione da decorare
@functools.wraps(funzione) # keep code inspection avaiable
@functools.wraps(funzione) # keep code inspection available
def wrapper(*args, **kwargs): # funzione decoratrice (args, kwargs sono argomenti della funzione decorata)
# do something before
var_funz = funzione(*args, **kwargs)
var_func = funzione(*args, **kwargs)
# do something after
return var_funz # restituisce il risultato della decorazione della funzione
return var_func # restituisce il risultato della decorazione della funzione
return wrapper # restituisce wrapper (chiamata a funz_decorata chiama wrapper)
return wrapper # restituisce wrapper (chiamata a func_decorata chiama wrapper)
@decorator # applicazione del decoratore alla funzione
def funzione(): # funzione da decorare
@ -1190,9 +1178,9 @@ def decorator(*dec_args, **dec_kwargs): # prende in input argomenti del decorat
def inner_wrapper(*args, **kwargs):
# do something before
var_funz = funzione(*args, **kwargs)
var_func = funzione(*args, **kwargs)
# do something after
return var_funz
return var_func
return inner_wrapper
@ -1213,14 +1201,14 @@ def funzione(): # funzione da decorare
class NomeClasse:
# creazione variabile statica (o di classe; condivisa da tutte le istanze)
# ovverride possinile tramite subclassing o assegnazine diretta (oggetto.static_var =)
# override possibile tramite subclassing o assegnazione diretta (oggetto.static_var =)
# NomeClasse.static_var = cambia l'attributo di classe in tutte le istanze
static_var = espressione
def __init__(self, valore_1, valore_2): # costruttore di default parametrizzato
# attributi sono alias degli argomenti (modifiche in-place cambiano argomenti)
self.variabile = valore_1 # creazione variabili di istanza
self.__variabile = valore_2 # variabile appartenente ad oggetti della classe e non ai figli, accesso tarmite NAME MANGLING
self.__variabile = valore_2 # variabile appartenente ad oggetti della classe e non ai figli, accesso tramite NAME MANGLING
@classmethod # metodo agente sulla classe e non sull'oggetto (utile x costruttori alternativi)
@ -1234,14 +1222,14 @@ class NomeClasse:
return espressione
@staticmethod # indica un metodo statico (NECESSARIO)
def metodo_statico(parametri): # metodi statici non influenzano variabili di istanza (SELF non necessatio)
def metodo_statico(parametri): # metodi statici non influenzano variabili di istanza (SELF non necessario)
instruction
return espressione
oggetto = NomeClasse(parametri) # creazione di un oggetto
oggetto.variabile = espressione # modifica variabile pubblica
oggetto.metodo(parametri) # invocazione metodo di istanza
NomeClasse.metodo(parametri) #ivocazione metodo statico
NomeClasse.metodo(parametri) # invocazione metodo statico
oggetto._NomeClasse__var_privata # accesso a variabile specificando la classe di appartenenza (NAME MANGLING)
```
@ -1260,7 +1248,7 @@ class NomeClasse:
return self.__parametro
@parametro.setter
def parameto(self, valore):
def parametro(self, valore):
self.__parametro = valore
@parametro.deleter # metodo deleter
@ -1271,12 +1259,12 @@ class NomeClasse:
### `__slots__`
L'attributo `__slots__` implementa **Flyweight Design Pattern**:
salva gli attributi d'istanza in una tupla e può essere usato per diminuire il costo in memoria inserendovi solo le variabili di istanza (sopprime il dizionario dell'istanza).
salva gli attributi d'istanza in una tuple e può essere usato per diminuire il costo in memoria inserendovi solo le variabili di istanza (sopprime il dizionario dell'istanza).
**Default**: attributi salvati in un dizionario (`oggetto.__dict__`)
**Uso**: `__slots_ = [attributi]`
`__slots__` non viene ereditato dalle sottoclassi, impedisce l'aggiunta dinamica delgi attributi.
`__slots__` non viene ereditato dalle sottoclassi, impedisce l'aggiunta dinamica degli attributi.
### Fluent Interface
@ -1324,7 +1312,7 @@ I metodi speciali sono definiti dall'uso di doppi underscore; essi permettono l'
class NomeClasse():
def __init__(self, parametri):
istuzioni
istruzioni
# usato da metodo str() e print()
# gestisce le richieste di rappresentazione come stringa
@ -1334,8 +1322,8 @@ class NomeClasse():
def __len__(self):
return espressione # necessario return in quanto len richiede una lunghezza/dimensione
def __del__(self): # elimina l'istanda della classe
instruction # eventuali istruzionni che avvengono all'eliminazione
def __del__(self): # elimina l'istanza della classe
instruction # eventuali istruzioni che avvengono all'eliminazione
oggetto = NomeClasse()
len(oggetto) # funzione speciale applicata ad un oggetto
@ -1363,7 +1351,7 @@ __xor__(self, other) # ^
__or__(self, other) # |
# operatori aritmetici riflessi
# [se self.__dunde__(other) fallisce viene chiamato other.__dunder__(self)]
# [se self.__dunder__(other) fallisce viene chiamato other.__dunder__(self)]
__radd__(self, other) # reverse +
__rsub__(self, other) # reverse -
__rmul__(self, other) # reverse *

6
Python/Standard Library/argparse.md
View file

@ -45,7 +45,7 @@ ArgumentParser.add_argument("name_or_flags", nargs="...", action="...")
### Actions
`store`: This just stores the argument’s value. This is the default action.
`store`: This just stores the argument's value. This is the default action.
```py
>>> parser = argparse.ArgumentParser()
@ -159,7 +159,7 @@ Namespace(bar='XX', foo='c')
Namespace(bar='d', foo='d')
```
`*`: All command-line arguments present are gathered into a list. Note that it generally doesn’t make much sense to have more than one positional argument with `nargs='*'`, but multiple optional arguments with `nargs='*'` is possible.
`*`: All command-line arguments present are gathered into a list. Note that it generally doesn't make much sense to have more than one positional argument with `nargs='*'`, but multiple optional arguments with `nargs='*'` is possible.
```py
>>> parser = argparse.ArgumentParser()
@ -170,7 +170,7 @@ Namespace(bar='d', foo='d')
Namespace(bar=['1', '2'], baz=['a', 'b'], foo=['x', 'y'])
```
`+`: All command-line args present are gathered into a list. Additionally, an error message will be generated if there wasn’t at least one command-line argument present.
`+`: All command-line args present are gathered into a list. Additionally, an error message will be generated if there wasn't at least one command-line argument present.
```py
>>> parser = argparse.ArgumentParser(prog='PROG')

2
Python/Standard Library/collections.md
View file

@ -6,7 +6,7 @@
# sottoclasse dizionario per contare oggetti hash-abili
from collections import Counter
Counter(sequenza) # -> oggetto Counter
# {item: num comparese in sequenza, ...}
# {item: num comprese in sequenza, ...}
var = Counter(sequenza)
var.most_common(n) # produce lista degli elementi più comuni (n più comuni)

10
Python/Standard Library/csv.md
View file

@ -29,10 +29,10 @@ fieldnames
# elimina il dialect associato a name
.unregister_dialect()
# restituisce il dialet associato a name
# restituisce il dialetto associato a name
.get_dialect(name)
# elenco dialec associati a name
# elenco dialetti associati a name
.list_dialect(name)
# restituisce (se vuoto) o setta il limite del campo del csv
@ -75,8 +75,8 @@ class csv.Sniffer
.has_header(campione) --> bool # True se prima riga è una serie di intestazioni di colonna
#COSTANTI
csv.QUOTE_ALL # indica a writer di citere (" ") tutti i campi
csv.QUOTE_MINIMAL # indica a write di citare solo i campi contenenti caratteri speciali come delimiter, quotechar ...
csv.QUOTE_NONNUMERIC # indica al vriter di citare tutti i campi non numerici
csv.QUOTE_ALL # indica a writer di citare (" ") tutti i campi
csv.QUOTE_MINIMAL # indica a write di citare solo i campi contenenti caratteri speciali come delimiter, quote char ...
csv.QUOTE_NONNUMERIC # indica al writer di citare tutti i campi non numerici
csv.QUOTE_NONE # indica a write di non citare mai i campi
```

33
Python/Standard Library/ftplib.md
View file

@ -1,14 +1,13 @@
# Ftplib Module Cheat Sheet
# Ftplib Module
## FTP CLASSES
```py
# restiuisce istanza classe FTP
ftplib.FTP(host="", user="", password="", acct="")
# se HOST fornito esegue connect(host)
# SE USER fornito esegue login(user, password, acct)
# if HOST => connect(host)
# if USER => login(user, password, acct)
# sottoclasse FTP con TLS
ftplib.FTP_TLS(host="", user="", password="", acct="")
```
@ -18,7 +17,7 @@ ftplib.FTP_TLS(host="", user="", password="", acct="")
ftplib.error_reply # unexpected error from server
ftplib.error_temp # temporary error (response codes 400-499)
ftplib.error_perm # permanent error (response codes 500-599)
ftplib.error_proto # error not in ftp specs
ftplib.error_proto # error not in ftp specs
ftplib.all_errors # tuple of all exceptions
```
@ -29,43 +28,43 @@ ftplib.all_errors # tuple of all exceptions
# method on binary files: -binary
# CONNECTION
FTP.connect(host="", port=0) # used unce per instance
# DONT CALL if host was supplied at instance creation
FTP.connect(host="", port=0) # used once per instance
# DON'T CALL if host was supplied at instance creation
FTP.getwelcome() # return welcome message
FTP.login(user='anonymous', password='', acct='')
# called unce per instance after connection is established
# DEAFAULT PASSWORD: anonymous@
# DONT CALL if host was supplied at instance creation
# called once per instance after connection is established
# DEFAULT PASSWORD: anonymous@
# DON'T CALL if host was supplied at instance creation
FTP.sendcmd(cmd) # send command string and return response
FTP.voidcmd(cmd) # send command string and return nothing if successful
# FILE TRANSFER
FTP.abort() # abort in progress file transfer (can fail)
FTTP.transfercmd(cmd, rest=None) # returns socket for connection
# CMD avtive mode: send EPRT or PORT command and CMD and accept connection
# CMD active mode: send EPRT or PORT command and CMD and accept connection
# CMD passive mode: send EPSV or PASV and start transfer command
FTP.retrbinary(cmd, callback, blocksize=8192, rest=None) # retrieve file in binary mode
# CMD: appropriate RETR comkmand ('RETR filename')
# CMD: appropriate RETR command ('RETR filename')
# CALLBACK: func called on every block of data received
FTP.rertlines(cmd, callback=None)
# retrieve file or dir list in ASCII transfer mode
# CMD: appropriate RETR, LSIT (list and info of files), NLST ( list of file names)
# CMD: appropriate RETR, LSIT (list and info of files), NLST (list of file names)
# DEFAULT CALLBACK: sys.stdout
FTP.set_pasv(value) # set passive mode if value is true, otherwise disable it
# passive mode on by deafultù
# passive mode on by default
FTP.storbinary(cmd, fp, blocksize=8192, callback=None, rest=None) # store file in binary mode
# CMD: appropriate STOR command ('STOR filename')
# FP: {file object in binary mode} read until EOF in blocks of blocksize
# CLABBACK: func called on each bloak after sending
# CALLBACK: func called on each block after sending
FTP.storlines(cmd, fp, callback=None) # store file in ASCII transfer mode
# CMD: appropriate STOR command ('STOR filename')
# FP: {file object} read until EOF
# CLABBACK: func called on each bloak after sending
# CALLBACK: func called on each block after sending
```

42
Python/Standard Library/functools.md
View file

@ -1,42 +0,0 @@
# Functools Module Cheat Sheet
Hiegher-order functions and operations on callable objects.
```py
# crea nuova funzione con argomenti (*args, **kwarg) parzialmente fissati
new_func = partial(func, *args, **kwargs)
# crea nuovo metodo con argomenti (*args, **kwarg) parzialmente fissati
new_method = partialmethod(func, *args, **kwargs)
# applica ripetutamente funzione( , ) all'iterabile per creare un output singolo
# funzione applicata ai primi due elementi
# restituisce inizzializzatore se l'iterabile è vuoto (dipendente dalla funzione)
reduce(funzione((arg_1, arg_2), iterabile, inizzializzatore) # -> singolo output
# decoratore che salva maxsixe:int chiamate recenti in cache
# utilizza dizionario per memorizzazione, argomenti (posizionali e keyworded devono essere hashabili)
# se maxsixe=None cache cresce indefinitivamente e feature LRU è disattivata
# LRU --> Least Recent Used. Elementi poco usati rimossi dalla cache
# per efficienza maxsize=2**n
@lru_cache(maxsize=128, typed=False)
# decoratore che trasforma la funzione in una single-dispatch generic function
# generic function --> singola funzione implementa la stessa operazione per tipi diversi (ALTERNATIVA A METHOD OVERLOAD)
# single dispatch --> forma di generic function in cui l'implementazione è decissa in base ad un singolo argomento
# ATTENZIONE: single dispatch deciso dal primo argomento
@singledispatch # crea decorated_func.register per raggruppare funzioni in una generic function
@decorated_func.register() # decide implementazione basandosi su type annotation
@decorated_func.register(type) # decide implementazione secondo argomento type (da usare se non è presente type annotation)
# il nome di decorated_func è irrilevante
# è utile usare register(type) su ABC per supportare classi più generiche e classi future
# decoratore per aggiornare wrapper function per apparire come wrapperd function
# funz_decoratrice mantiene argomenti e docstring della funzione decorata
def decorator(funzione):
@wraps(funzione)
def wrapper(): #funz_decoratrice dentro decorator
# crea operatori uguaglianza se classe ne implementa almeno uno e __eq__()
@total_ordering
```

67
Python/Standard Library/itertools.md
View file

@ -1,56 +1,51 @@
# Itertools Module
```py
# iteratore restituisce somma cumulativa, se presente viene applicata func( , )
# accumulate([1,2,3,4,5]) -> 1, 3(1+2), 6(1+2+3), 10(1+2+3+6), 15(1+2+3+4+5)
# accumulate(iter, func( , )) -> iter[0], func(iter[0] + iter[1]) + func(ris_prec + iter[2]), ...
accumulate(iterabile, func(_, _))
# accumulate(iter, func( , )) -> iter[0], func(iter[0] + iter[1]) + func(prev + iter[2]), ...
accumulate(iterable, func(_, _))
# iteratore restituisce elemenmti dal primo iterabile,
# iteratore restituisce elementi dal primo iterable,
# poi procede al successivo fino alla fine degli iterabili
# non funziona se l'iterabile è uno solo
# non funziona se l'iterable è uno solo
chain(*iterabili)
ChainMap(*maps) # A ChainMap groups multiple dicts or other mappings together to create a single, updateable view. Lookups search the underlying mappings successively until a key is found. A ChainMap incorporates the underlying mappings by reference. So, if one of the underlying mappings gets updated, those changes will be reflected in ChainMap
# concatena elementi del singolo iterable anche se contiene sequenze
chain.from_iterable(iterable)
# concatena elementi del singolo iterabile anche se contiene sequenze
chain.from_iterable(iterabile)
# restituisce sequenze di lunghezza r a partire dall'iterabile
# restituisce sequenze di lunghezza r a partire dall'iterable
# elementi trattati come unici in base al loro valore
combinations(iterabile, r)
combinations(iterable, r)
# # restituisce sequenze di lunghezza r a partire dall'iterabile permettendo la ripetizione degli elementi
combinations_with_replacement(iterabile, r)
# # restituisce sequenze di lunghezza r a partire dall'iterable permettendo la ripetizione degli elementi
combinations_with_replacement(iterable, r)
# iteratore filtra elementi di data restituenso solo quelli che hanno
# iteratore filtra elementi di data restituendo solo quelli che hanno
# un corrispondente elemento in selectors che ha valore vero
compress(data, selectors)
# iteratore restituiente valori equidistanti a partire da start
#! ATTENZIONE: sequenza numerica infinita
count(start, step)
# iteratore restituiente valori in sequenza infinita
cycle(iterabile)
# iteratore restituente valori in sequenza infinita
cycle(iterable)
# iteratore droppa elementi dell'iterabile finchè il predicato è vero
dropwhile(predicato, iterabile)
# iteratore scarta elementi dell'iterable finché il predicato è vero
dropwhile(predicato, iterable)
# iteratore restituiente valori se il predicato è falso
filterfalse(predicato, iterabile)
# iteratore restituente valori se il predicato è falso
filterfalse(predicato, iterable)
# iteratore restituisce tuple (key, group)
# key è il criterio di raggruppamento
# group è un generatore restituiente i membri del gruppo
groupby(iterabile, key=None)
# group è un generatore restituente i membri del gruppo
groupby(iterable, key=None)
# iteratore restituisce slice dell'iterabile
# iteratore restituisce slice dell'iterable
isslice(iterable, stop)
isslice(iterable, start, stop, step)
# restituisce tutte le permutazioni di lunghezza r dell'iterabile
permutations(iterabile, r=None)
# restituisce tutte le permutazioni di lunghezza r dell'iterable
permutations(iterable, r=None)
# prodotto cartesiano degli iterabili
# cicla iterabili in ordine di input
@ -61,17 +56,17 @@ product(*iterabili, ripetizioni=1)
# restituisce un oggetto infinite volte se ripetizioni non viene specificato
repeat(oggetto, ripetizioni)
# iteratore computa func(iterabile)
# usato se iterabile è sequenza pre-zipped (seq di tuple raggruppanti elementi)
starmap(func, iterabile)
# iteratore computa func(iterable)
# usato se iterable è sequenza pre-zipped (seq di tuple raggruppanti elementi)
starmap(func, iterable)
# iteratore restituiente valori da iterabile finchè predicato è vero
takewhile(predicato, iterabile)
# iteratore restituente valori da iterable finché predicato è vero
takewhile(predicato, iterable)
# restituisce n iteratori indipendenti dal singolo iterabile
tee(iterabile, n=2)
# restituisce n iteratori indipendenti dal singolo iterable
tee(iterable, n=2)
# produce un iteratore che aggrega elementi da ogni iterabile
# produce un iteratore che aggrega elementi da ogni iterable
# se gli iterabili hanno lunghezze differenti i valori mancanti sono riempiti secondo fillervalue
zip_longest(*iterabile, fillvalue=None)
zip_longest(*iterable, fillvalue=None)
```

10
Python/Standard Library/json.md
View file

@ -65,7 +65,7 @@ json.loads(s, cls=None)
## Default Decoder (`json.JSONDecoder()`)
Convertions (JSON -> Python):
Conversions (JSON -> Python):
- object -> dict
- array -> list
@ -78,7 +78,7 @@ Convertions (JSON -> Python):
## Default Encoder (`json.JSONEncoder()`)
Convertions (Python -> Json):
Conversions (Python -> Json):
- dict -> object
- list, tuple -> array
@ -96,7 +96,7 @@ import json
class ComplexEncoder(json.JSONEncoder):
def default(self, obj):
if isinstance(obj, complex):
return [obj.real, obj.imag]
return [obj.real, obj.image]
# Let the base class default method raise the TypeError
return json.JSONEncoder.default(self, obj)
```
@ -105,6 +105,6 @@ class ComplexEncoder(json.JSONEncoder):
```python
data = json.loads(json)
data["key"] # retieve the value associated with the key
data["outer key"]["nested key"] # nested key value retireval
data["key"] # retrieve the value associated with the key
data["outer key"]["nested key"] # nested key value retrieval
```

18
Python/Standard Library/logging.md
View file

@ -1,4 +1,4 @@
# Logging Module Cheat Sheet
# Logging Module
## Configuration
@ -41,24 +41,24 @@ logging.disable(level=LOG_LEVEL)
| Directive | Meaning |
|-----------|------------------------------------------------------------------------------------------------------------------------------|
| `%a` | Locale’s abbreviated weekday name. |
| `%A` | Locale’s full weekday name. |
| `%b` | Locale’s abbreviated month name. |
| `%B` | Locale’s full month name. |
| `%c` | Locale’s appropriate date and time representation. |
| `%a` | Locale's abbreviated weekday name. |
| `%A` | Locale's full weekday name. |
| `%b` | Locale's abbreviated month name. |
| `%B` | Locale's full month name. |
| `%c` | Locale's appropriate date and time representation. |
| `%d` | Day of the month as a decimal number [01,31]. |
| `%H` | Hour (24-hour clock) as a decimal number [00,23]. |
| `%I` | Hour (12-hour clock) as a decimal number [01,12]. |
| `%j` | Day of the year as a decimal number [001,366]. |
| `%m` | Month as a decimal number [01,12]. |
| `%M` | Minute as a decimal number [00,59]. |
| `%p` | Locale’s equivalent of either AM or PM. |
| `%p` | Locale's equivalent of either AM or PM. |
| `%S` | Second as a decimal number [00,61]. |
| `%U` | Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. |
| `%w` | Weekday as a decimal number [0(Sunday),6]. |
| `%W` | Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. |
| `%x` | Locale’s appropriate date representation. |
| `%X` | Locale’s appropriate time representation. |
| `%x` | Locale's appropriate date representation. |
| `%X` | Locale's appropriate time representation. |
| `%y` | Year without century as a decimal number [00,99]. |
| `%Y` | Year with century as a decimal number. |
| `%z` | Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM [-23:59, +23:59]. |

57
Python/Standard Library/operator.md
View file

@ -9,14 +9,14 @@ __ne__(a, b), ne(a, b) # a != b
__ge__(a, b), ge(a, b) # a >= b
__gt__(a, b), gt(a, b) # a > b
# OPERATOTI LOGICI
not_(obj) # not obj
truth(obj) # True o Flase ini base a valore verità oggetto (come costruttore bool)
is_(a, b) # return a is b
is_not(a, b) # return a is not b
# OPARATORI BINARI E MATEMATICI
__abs__(a, b), abs(obj) # valore assoluto di obj
not_(obj)
truth(obj)
is_(a, b)
is_not(a, b)
__abs__(a, b), abs(obj)
__add__(a, b), add(a, b) # a + b
__sub__(a, b), sub(a, b) # a - b
__mul__(a,b), mul(a,b) # a * b
@ -25,37 +25,20 @@ __truediv__(a, b), truediv(a, b) # a / b
__floordiv__(a, b), floordiv(a, b) # return a // b
__mod__(a, b), mod(a, b) # a % b
__neg__(obj), neg(obj) # -obj
__index__(a), index(a) # converte a in intero
__index__(a), index(a)
__and__(a, b), and_(a, b) # a and b binario (a & b)
__or__(a, b), or_(a, b) # a or b binario (a | b)
__xor__(a, b), xor(a, b) # a xor b binario (a ^ b)
__and__(a, b), and_(a, b) # a & b
__or__(a, b), or_(a, b) # a | b
__xor__(a, b), xor(a, b) # a ^ b
__inv__(obj), inv(obj), __inverse__(obj), inverse(obj) # inverso binario di obj, ~obj
__lshift__(obj), lshift(a, b) # restituisce a spostato a sinistra di b
__inv__(obj), inv(obj), __inverse__(obj), inverse(obj) # ~obj
__lshift__(obj), lshift(a, b)
__concat__(a, b), concat(a, b) # a + b per sequenze (CONCATENZIONE)
__contains__(a, b), contains(a, b) # return b in a
countOf(a, b) # numero occorrenze b in a
indexOF(a, b) # restituisce prima occorrenza di b in a
__concat__(a, b), concat(a, b)
__contains__(a, b), contains(a, b)
countOf(a, b)
indexOf(a, b)
__delitem__(a, b), delitem(a, b) # rimuove valore a in posizione b
__getitem__(a, b), getitem(a, b) # restituisce valore a in posizione b
__setitem__(a, b), setitem(a, b) # setta valore a in psoizione b
# ATTRGETTER
# restituisce oggetto chiamabile che recupera attributo attr da oggetto
funz = attrgetter(*attr)
funz(var) # restituisce var.attr
# ITEMGETTER
# restituisce oggetto chiamabile che recupera item dall'oggetto
# implementa __getitem__
funz = itemgetter(*item)
funz(var) # restituisce var[item]
# METHODCALLER
# restutiusce oggetto che chiama metodo method sull'oggetto
var = methodcaller(method, args)
var(obj) # return obj.method()
```
__delitem__(a, b), delitem(a, b)
__getitem__(a, b), getitem(a, b)
__setitem__(a, b), setitem(a, b)

60
Python/Standard Library/os.md
View file

@ -1,60 +0,0 @@
# OS Cheat Sheet
```python
os.curdir # stringa identificante cartella corrente ("." per WIN)
os.pardir # stringa identificante cartella genitore (".." per WIN)
os.sep # carattere separatore in path (\\ per WIN, / per POSIX)
os.extsep # carattere separatore estensione file (".")
os.pathsep # carattere separatore in ENVVAR PATH (";" per WIN, ":" per POSIX)
os.linesp # stringa usata per separare linee (\r\n per WIN, \n per POSIX)
os.system("command") # execute command in shell
os.remove(path) # cancella il file indicato da path
os.rmdir(path) # cancella cartella indicata da path
os.listdir(path) # restituisce lista nomi dei contenuti cartella
os.path.exists(path) # True se path si riferisce ad elemento esistente
os.path.split() # divide path in (head, tail), head + tail == path
os.path.splitdrive(path) # divide path in (drive, tail), drive + tail == path
os.path.splitext() # divide path in (root, ext), root + ext == path
os.path.dirname(path) # restituisce nome cartella (path head)
os.path.getatime(path) # restituisce data ultimo accesso
os.path.getmtime(path) # restituisce data ultima modifica
os.path.getsize(path) # restituisce dimesione in bytes (OSError se file inaccessibile o inesistente)
os.path.isfile(path) # True se path è file esistente
os.path.isdir(path) # True se path è cartella esistente
os.path.join(path, *paths) # concatena vari path
os.path.realpath(path) # Return the canonical path of the specified filename, eliminating symbolic links
os.path.relpath(path, start=os.curdir) # restituisce path relativo (start opzionale, default os.curdir)
os.path.abspath(path) # return a normalized absolutized version of the pathname path
# collapses redundant separators and up-level references so that A//B, A/B/, A/./B and A/foo/../B all become A/B
os.walk(top)
# Generate the file names in a directory tree by walking the tree either top-down or bottom-up.
# For each directory in the tree rooted at directory top (including), it yields a 3-tuple (dirpath, dirnames, filenames).
# dirpath is a string, the path to the directory.
# dirnames is a list of the names of the subdirectories in dirpath (excluding '.' and '..').
# filenames is a list of the names of the non-directory files in dirpath.
```
## Folder Operations
```python
os.getcwd() # Return a string representing the current working directory
os.chdir(path) # change the current working directory to path
os.mkdir(path, mode=0o777) # Create a directory named path with numeric mode MODE.
os.makedirs(name, mode=0o777) # Recursive directory creation
```
## Exceptions
```python
IsADirectoryError # file operation requested on directory
NotADirectoryError # directory operation requested on file
```

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