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@ -2,7 +2,7 @@
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[PHP Docs](https://www.php.net/docs.php)
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```php
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```php linenums="1"
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declare(strict_types=1); # activates variable type checking on function arguments
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# single line comment
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//single line comment
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@ -11,7 +11,7 @@ declare(strict_types=1); # activates variable type checking on function argumen
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## Include, Require
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```php
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```php linenums="1"
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include "path\\file.php"; # import an external php file, E_WARNING if fails
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include_once "path\\file.php"; # imports only if not already loaded
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@ -23,7 +23,7 @@ require_once "path\\file.php"; # imports only if not already loaded
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In `config.php`:
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```php
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```php linenums="1"
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//config.php
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//store configuration options in associative array
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@ -33,7 +33,7 @@ return [
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]
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```
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```php
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```php linenums="1"
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$config = include "config.php"; // retrieve config and store into variable
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```
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@ -41,7 +41,7 @@ $config = include "config.php"; // retrieve config and store into variable
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[PSR-4 Spec](https://www.php-fig.org/psr/psr-4/)
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```php
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```php linenums="1"
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namespace Foo\Bar\Baz; # set namespace for all file contents, \ for nested namespaces
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use <PHP_Class> # using a namespace hides standard php classes (WHY?!?)
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@ -68,7 +68,7 @@ fnn\func(); # use function from Foo\Bar\Baz
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## Basics
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```php
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```php linenums="1"
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declare(strict_types=1); # activates type checking
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# single line comment
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//single line comment
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|
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@ -77,7 +77,7 @@ declare(strict_types=1); # activates type checking
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### Screen Output
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```php
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```php linenums="1"
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echo "string"; # string output
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echo 'string\n'; # raw string output
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printf("format", $variables); # formatted output of strings and variables
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@ -86,7 +86,7 @@ sprintf("format", $variables); # return formatted string
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### User Input
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```php
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```php linenums="1"
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$var = readline("prompt");
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# if readline is not installed
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@ -105,7 +105,7 @@ if (!function_exists('readline')) {
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## Variables
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```php
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```php linenums="1"
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$variableName = value; # weakly typed
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echo gettype(&variable); # output type of variable
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@ -114,7 +114,7 @@ var_dump($var); # prints info of variable (bit dimension, type & value)
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### Integers
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```php
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```php linenums="1"
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&max = PHP_INT_MAX; # max value for int type -> 9223372036854775807
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&min = PHP_INT_MIN; # min value for int type -> -9223372036854775808
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&bytes = PHP_INT_SIZE; # bytes for int type -> 8
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@ -127,7 +127,7 @@ var_dump($var); # prints info of variable (bit dimension, type & value)
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### Double
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```php
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```php linenums="1"
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$a = 1.234; // 1.234
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$b = 1.2e3; // 1200
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$c = 7E-10; // 0.0000000007
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@ -163,14 +163,14 @@ A string is a sequence of ASCII characters. In PHP a string is an array of chara
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### String Concatenation
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```php
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```php linenums="1"
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$string1 . $string2; # method 1
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$string1 .= $string2; # method 2
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```
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### String Functions
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```php
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```php linenums="1"
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strlen($string); # returns the string length
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strpos($string, 'substring'); # position of substring in string
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substr($string, start, len); # extract substring of len from position start
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@ -184,7 +184,7 @@ $var = sprintf("format", $variables) # construct and return a formatted string
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## Constants
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```php
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```php linenums="1"
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define ('CONSTANT_NAME', 'value')
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```
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@ -201,7 +201,7 @@ define ('CONSTANT_NAME', 'value')
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Heterogeneous sequence of values.
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```php
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```php linenums="1"
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$array = (sequence_of_items); # array declaration and valorization
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$array = [sequence_of_items]; # array declaration and valorization
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@ -216,7 +216,7 @@ $array[] = value; # value appending
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Array of array. Can have arbitrary number of nested array
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```php
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```php linenums="1"
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$matrix = [
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[1, 2, 3],
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[4, 5, 6],
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@ -228,14 +228,14 @@ $matrix = [
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Single instruction to print whole array is ``
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```php
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```php linenums="1"
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$array = [1, 2, 3];
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print_r($array); # print all the array values
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```
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### Array Functions
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```php
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```php linenums="1"
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count($array); # returns number of items in the array
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array_sum($array) # sum of the array value
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sort($array); # quick sort
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@ -263,7 +263,7 @@ list($array1 [, $array2, ...]) = $data; # Python-like tuple unpacking
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Associative arrays have a value as an index. Alternative names are _hash tables_ or _dictionaries_.
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```php
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```php linenums="1"
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$italianDay = [
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'Mon' => 'Lunedì',
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'Tue' => 'Martedì',
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@ -309,14 +309,14 @@ With `==` a string evaluates to `0`.
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### Ternary Operator
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```php
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```php linenums="1"
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condition ? result_if_true : result_if_false;
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condition ?: result_if_false;
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```
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### NULL Coalesce
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```php
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```php linenums="1"
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$var1 = $var2 ?? value; # if variable == NULL assign value, otherwise return value of $var2
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# equivalent to
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@ -325,7 +325,7 @@ $var1 = isset($var2) ? $var2 : value
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### Spaceship Operator
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```php
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```php linenums="1"
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$a <=> $b;
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# equivalent to
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@ -339,7 +339,7 @@ if $a < $b
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### `If` - `Elseif` - `Else`
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```php
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```php linenums="1"
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if (condition) {
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# code here
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} elseif (condition) {
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@ -359,7 +359,7 @@ endif;
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### Switch Case
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```php
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```php linenums="1"
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# weak comparison
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switch ($var) {
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case value:
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@ -385,7 +385,7 @@ switch (true) {
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`match` can return values, doesn't require break statements, can combine conditions, uses strict type comparisons and doesn't do any type coercion.
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```php
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```php linenums="1"
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$result = match($input) {
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0 => "hello",
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'1', '2', '3' => "world",
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|
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@ -396,7 +396,7 @@ $result = match($input) {
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### For, Foreach
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```php
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```php linenums="1"
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for (init, condition, increment){
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# code here
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}
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@ -421,7 +421,7 @@ foreach($sequence as $key => $value) {
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### While, Do-While
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```php
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```php linenums="1"
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while (condition) {
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# code here
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}
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@ -447,7 +447,7 @@ do {
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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.
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```php
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```php linenums="1"
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declare(strict_types=1); # activates type checking
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/**
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@ -475,7 +475,7 @@ function functionName (type $parameter, $parameter = default_value): Type
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### Void function
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```php
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```php linenums="1"
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function functionName (type $parameter, $parameter = default_value): Void
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{
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# code here
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@ -484,7 +484,7 @@ function functionName (type $parameter, $parameter = default_value): Void
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### Passing a parameter by reference (`&$`)
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```php
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```php linenums="1"
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function functionName (type &$parameter): Type
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{
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# code here
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@ -494,7 +494,7 @@ function functionName (type &$parameter): Type
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### Variable number of parameters, variadic operator (`...`)
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```php
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```php linenums="1"
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function functionName (type $parameter, ...$args): Type
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function functionName (type $parameter, type ...$args): Type
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{
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@ -505,7 +505,7 @@ function functionName (type $parameter, type ...$args): Type
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### Nullable parameters
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```php
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```php linenums="1"
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function functionName (?type $parameter): ?Type
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{
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# code here
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|
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@ -515,7 +515,7 @@ function functionName (?type $parameter): ?Type
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## Anonymous Functions (Closure)
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```php
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```php linenums="1"
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# declaration and assignment to variable
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$var = function (type $parameter) {
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# code here
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@ -526,7 +526,7 @@ $var($arg);
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### Use Operator
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```php
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```php linenums="1"
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# use imports a variable into the closure
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$foo = function (type $parameter) use ($average) {
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# code here
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@ -537,7 +537,7 @@ $foo = function (type $parameter) use ($average) {
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**Union types** are a collection of two or more types which indicate that _either_ one of those _can be used_.
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```php
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```php linenums="1"
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public function foo(Foo|Bar $input): int|float;
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```
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@ -546,7 +546,7 @@ public function foo(Foo|Bar $input): int|float;
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Named arguments allow to pass in values to a function, by specifying the value name, to avoid taking their order into consideration.
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It's also possible to skip optional parameters.
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```php
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```php linenums="1"
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function foo(string $a, string $b, ?string $c = null, ?string $d = null) { /* … */ }
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foo(
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@ -568,7 +568,7 @@ foo(
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### Class Declaration & Instantiation
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```php
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```php linenums="1"
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# case insensitive
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class ClassName
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{
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|
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@ -611,7 +611,7 @@ $object instanceof ClassName // check type of the object
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Inside static methods it's impossible to use `$this`.
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A static variable is unique for the class and all instances.
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```php
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```php linenums="1"
|
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class ClassName {
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public static $var;
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|
|
@ -636,7 +636,7 @@ $obj::$var; // access to the static variable
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|
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Parameters of the dependency can be modified before passing the required class to the constructor.
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```php
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```php linenums="1"
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class ClassName
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{
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private $dependency;
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|
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@ -653,7 +653,7 @@ class ClassName
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If a class is defined `final` it can't be extended.
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If a function is declared `final` it can't be overridden.
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|
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```php
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```php linenums="1"
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class Child extends Parent
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{
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public __construct() {
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|
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@ -666,7 +666,7 @@ class Child extends Parent
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|
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Abstract classes cannot be instantiated;
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|
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```php
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```php linenums="1"
|
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abstract class ClassName
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{
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# code here
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|
|
@ -679,7 +679,7 @@ An interface is a "contract" that defines what methods the implementing classes
|
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|
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A class can implement multiple interfaces but there must be no methods in common between interface to avoid ambiguity.
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|
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```php
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```php linenums="1"
|
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interface InterfaceName {
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// it is possible to define __construct
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|
|
@ -703,7 +703,7 @@ It can be used to mitigate the problem of _multiple inheritance_, which is absen
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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.
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```php
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```php linenums="1"
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trait TraitName {
|
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// code here
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}
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|
|
@ -716,7 +716,7 @@ class ClassName {
|
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|
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### Anonymous Classes
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|
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```php
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```php linenums="1"
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$obj = new ClassName;
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$obj->method(new class implements Interface {
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|
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@ -728,7 +728,7 @@ $obj->method(new class implements Interface {
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## Serialization & JSON
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```php
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```php linenums="1"
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$serialized = serialize($obj); # serialization
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$obj = unserialize($serialized); # de-serialization
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|
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|
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@ -740,7 +740,7 @@ $json = json_encode($value); # Returns a string containing the JSON representat
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### Read/Write on Files
|
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|
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```php
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```php linenums="1"
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file(filename); // return file lines in an array
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|
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// problematic with large files (allocates memory to read all file, can fill RAM)
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|
|
@ -750,7 +750,7 @@ file_get_contents(filename); // read whole file
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## Regular Expressions
|
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|
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```php
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```php linenums="1"
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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
|
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# $matches[0] = whole matched string
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# $matches[i] = i-th group of the regex
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|
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@ -774,7 +774,7 @@ Supported hashing algrithms:
|
|||
- `joaat`
|
||||
- `haval128,3`, `haval160,3`, `haval192,3`, `haval224,3`, `haval256,3`, `haval128,4`, `haval160,4`, `haval192,4`, `haval224,4`, `haval256,4`, `haval128,5`, `haval160,5`, `haval192,5`, `haval224,5`, `haval256,5`
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
||||
hash($algorithm, $data);
|
||||
```
|
||||
|
||||
|
|
@ -804,7 +804,7 @@ Algorithms currently supported:
|
|||
- **time_cost** (integer) - Maximum amount of time it may take to compute the Argon2 hash. Defaults to PASSWORD_ARGON2_DEFAULT_TIME_COST.
|
||||
- **threads** (integer) - Number of threads to use for computing the Argon2 hash. Defaults to PASSWORD_ARGON2_DEFAULT_THREADS.
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
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password_hash($password, $algorithm); # create a new password hash using a strong one-way hashing algorithm.
|
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password_verify($password, $hash); # Verifies that a password matches a hash
|
||||
```
|
||||
|
|
@ -817,17 +817,17 @@ Types of PHP errors:
|
|||
- **Warning**: generated at runtime, does not stop the execution (non-blocking).
|
||||
- **Notice**: informative errors or messages, non-blocking.
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
||||
$a = new StdClass()
|
||||
$a->foo(); // PHP Fatal Error: foo() does not exist
|
||||
```
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
||||
$a = 0;
|
||||
echo 1/$a; // PHP Warning: Division by zero
|
||||
```
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
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echo $a; // PHP Notice: $a undefined
|
||||
```
|
||||
|
||||
|
|
@ -837,7 +837,7 @@ echo $a; // PHP Notice: $a undefined
|
|||
|
||||
Its possible to configure PHP to signal only some type of errors. Errors below a certain levels are ignored.
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
||||
error_reporting(E_<type>); // set error report threshold (for log file)
|
||||
// does not disable PARSER ERROR
|
||||
|
||||
|
|
@ -847,7 +847,7 @@ ini_set("error_log", "path\\error.log"); // set log file
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|||
|
||||
### Triggering Errors
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
||||
// generate E_USER_ errors
|
||||
trigger_error("message"); // default type: E_USER_NOTICE
|
||||
trigger_error("message", E_USER_<Type>);
|
||||
|
|
@ -859,7 +859,7 @@ trigger_error("Deprecated Function", E_USER_DEPRECATED);
|
|||
|
||||
It's possible to use log files unrelated to the php log file.
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
||||
error_log("message", 3, "path\\log.log"); // write log message to a specified file
|
||||
|
||||
//example
|
||||
|
|
@ -870,7 +870,7 @@ error_log(sprintf("[%s] Error: _", date("Y-m-d h:i:s")), 3, "path\\log.log")
|
|||
|
||||
PHP offers the possibility to handle errors with the _exception model_.
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
||||
try {
|
||||
// dangerous code
|
||||
} catch(ExceptionType1 | ExceptionType2 $e) {
|
||||
|
|
@ -884,7 +884,7 @@ throw new ExceptionType("message"); // throw an exception
|
|||
|
||||
All exceptions in PHP implement the interface `Throwable`.
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
||||
Interface Throwable {
|
||||
abstract public string getMessage ( void )
|
||||
abstract public int getCode ( void )
|
||||
|
|
@ -899,7 +899,7 @@ Interface Throwable {
|
|||
|
||||
### Custom Exceptions
|
||||
|
||||
```php
|
||||
```php linenums="1"
|
||||
/**
|
||||
* Define a custom exception class
|
||||
*/
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue