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@ -10,6 +10,8 @@ This document describes PHP 5+.
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```php
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<?php // PHP code must be enclosed with <?php ? > tags
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// If your php file only contains PHP code, it is best practise to omit the php closing tag.
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// Two forward slashes start a one-line comment.
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# So will a hash (aka pound symbol) but // is more common
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@ -23,7 +25,7 @@ This document describes PHP 5+.
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print('Hello '); // Prints "Hello " with no line break
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// () are optional for print and echo
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echo 'World\n'; // Prints "World" with a line break
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echo "World\n"; // Prints "World" with a line break
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// (all statements must end with a semicolon)
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// Anything outside <?php tags is echoed automatically
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@ -40,13 +42,13 @@ echo 'World\n'; // Prints "World" with a line break
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// followed by any number of letters, numbers, or underscores.
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// Boolean values are case-insensitive
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$boolean = true; // or TRUE or True
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$boolean = true; // or TRUE or True
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$boolean = false; // or FALSE or False
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// Integers
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$int1 = 19; // => 19
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$int2 = -19; // => -19
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$int3 = 019; // => 15 (a leading 0 denotes an octal number)
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$int1 = 19; // => 19
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$int2 = -19; // => -19
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$int3 = 019; // => 15 (a leading 0 denotes an octal number)
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$int4 = 0x0F; // => 15 (a leading 0x denotes a hex literal)
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// Floats (aka doubles)
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@ -55,26 +57,26 @@ $float = 1.2e3;
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$float = 7E-10;
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// Arithmetic
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$sum = 1 + 1; // 2
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$sum = 1 + 1; // 2
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$difference = 2 - 1; // 1
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$product = 2 * 2; // 4
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$quotient = 2 / 1; // 2
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$product = 2 * 2; // 4
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$quotient = 2 / 1; // 2
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// Shorthand arithmetic
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$number = 0;
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$number += 1; // Add 1 to $number
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echo $number++; // Prints 1 (increments after evaluation)
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echo ++$number; // Prints 3 (increments before evalutation)
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$number += 1; // Increment $number by 1
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echo $number++; // Prints 1 (increments after evaluation)
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echo ++$number; // Prints 3 (increments before evalutation)
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$number /= $float; // Divide and assign the quotient to $number
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// Strings should be enclosed in single quotes;
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$sgl_quotes = '$String'; // => '$String'
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// Avoid using double quotes except to embed other variables
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$dbl_quotes = "This is a $sgl_quotes."; // => 'This is a $String'
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$dbl_quotes = "This is a $sgl_quotes."; // => 'This is a $String.'
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// Special characters are only escaped in double quotes
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$escaped = "This contains a \t tab character.";
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$escaped = "This contains a \t tab character.";
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$unescaped = 'This just contains a slash and a t: \t';
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// Enclose a variable in curly braces if needed
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@ -110,7 +112,7 @@ $associative = array('One' => 1, 'Two' => 2, 'Three' => 3);
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// PHP 5.4 introduced a new syntax
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$associative = ['One' => 1, 'Two' => 2, 'Three' => 3];
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echo $associative['One']; // prints "1"
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echo $associative['One']; // prints 1
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// List literals implicitly assign integer keys
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$array = ['One', 'Two', 'Three'];
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@ -133,8 +135,8 @@ print 'Hello World!'; // So is print
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$paragraph = 'paragraph';
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echo 100;
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echo $paragraph;
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echo 100; // Echo scalar variables directly
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echo $paragraph; // or variables
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// If short open tags are configured, or your PHP version is
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// 5.4.0 or greater, you can use the short echo syntax
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@ -144,10 +146,11 @@ echo $paragraph;
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$x = 1;
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$y = 2;
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$x = $y; // A now contains the same value sa $y
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$x = $y; // $x now contains the same value as $y
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$z = &$y;
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// $x now contains a reference to $y. Changing the value of
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// $x will change the value of $y also, and vice-versa.
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// $z now contains a reference to $y. Changing the value of
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// $z will change the value of $y also, and vice-versa.
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// $x will remain unchanged as the original value of $y
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echo $x; // => 2
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echo $z; // => 2
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@ -216,7 +219,7 @@ if (true) {
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}
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if (false) {
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print "I don't";
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print 'I don\'t';
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} else {
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print 'I get printed';
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}
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@ -251,7 +254,7 @@ This is displayed otherwise.
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switch ($x) {
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case '0':
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print 'Switch does type coercion';
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break; // You must include a break, or you will fall through
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break; // You must include a break, or you will fall through to cases 'two' and 'three'
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case 'two':
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case 'three':
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// Do something if $variable is either 'two' or 'three'
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@ -276,16 +279,16 @@ do {
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echo "\n";
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for ($x = 0; $x < 10; $x++) {
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echo $x; // Will echo 0 - 9
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}// Prints "0123456789"
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echo $x;
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} // Prints "0123456789"
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echo "\n";
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$wheels = ['bicycle' => 2, 'car' => 4];
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// Foreach loops can iterate over arrays
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foreach ($wheels as $wheel_count){
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echo "$wheel_count";
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foreach ($wheels as $wheel_count) {
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echo $wheel_count;
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} // Prints "24"
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echo "\n";
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@ -303,9 +306,9 @@ while ($i < 5) {
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break; // Exit out of the while loop
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}
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echo $i++;
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}// Prints "012"
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} // Prints "012"
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for($i = 0; $i < 5; $i++){
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for ($i = 0; $i < 5; $i++) {
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if ($i === 3) {
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continue; // Skip this iteration of the loop
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}
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@ -318,7 +321,7 @@ for($i = 0; $i < 5; $i++){
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*/
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// Define a function with "function":
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function my_function() {
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function my_function () {
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return 'Hello';
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}
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@ -327,7 +330,7 @@ echo my_function(); // => "Hello"
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// A valid function name starts with a letter or underscore, followed by any
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// number of letters, numbers, or underscores.
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function add($x, $y = 1) { // $y is optional, and defaults to 2
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function add ($x, $y = 1) { // $y is optional and defaults to 1
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$result = $x + $y;
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return $result;
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}
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@ -339,7 +342,7 @@ echo add(4, 2); // => 6
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// print $result; // Gives a warning.
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// Since PHP 5.3 you can declare anonymous functions;
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$inc = function($x){
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$inc = function ($x) {
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return $x + 1;
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};
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@ -358,78 +361,92 @@ function bar ($x, $y) {
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}
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$bar = bar('A', 'B');
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$bar('C');
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$bar('C'); // Prints "A - B - C"
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// You can call named functions using strings
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$function_name = 'add';
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echo $function_name(1, 2); // => 3
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// But, you should probably use anonymous functions instead.
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// Useful for programatically determining which function to run.
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// Alternatively, use call_user_func(callable $callback [, mixed $parameter [, mixed $... ]]);
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/********************************
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* Classes
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*/
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//Classes are defined with the class keyword
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// Classes are defined with the class keyword
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class MyClass {
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const MY_CONST = 'value'; // A constant
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static $staticVar = 'static';
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public $property = 'public'; // Properties must declare their visibility
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private $privprop = 'private'; // Accessible within the class only
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protected $protprop = 'protected'; // Accessible within the class and subclasses
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class MyClass
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{
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const MY_CONST = 'value'; // A constant
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static $staticVar = 'static';
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// Properties must declare their visibility
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public $property = 'public';
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public $instanceProp;
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protected $protProp = 'protected'; // Accessible within the class and subclasses
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private $privProp = 'private'; // Accessible within the class only
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// Create a constructor with __construct
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public function __construct($instanceProp){
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public function __construct($instanceProp) {
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// Access instance variables with $this
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$this->instanceProp = $instanceProp;
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}
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// Methods are declared as functions inside a class
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public function myMethod() {
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print "MyClass";
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public function myMethod()
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{
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print 'MyClass';
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}
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final function youCannotOverrideMe() {
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final function youCannotOverrideMe()
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{
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}
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public static function myStaticMethod() {
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print "I am static";
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public static function myStaticMethod()
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{
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print 'I am static';
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}
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}
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echo MyClass::MY_CONST; // Outputs "value";
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echo MyClass::$staticVar; // Outputs 'static';
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MyClass::myStaticMethod(); // Outputs "I am static";
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echo MyClass::MY_CONST; // Outputs 'value';
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echo MyClass::$staticVar; // Outputs 'static';
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MyClass::myStaticMethod(); // Outputs 'I am static';
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// Access class members using ->.
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$my_class = new MyClass("An instance property"); // The parentheses are optional.
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echo $my_class->property; // => "public"
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// Access class members using ->
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$my_class = new MyClass('An instance property'); // The parentheses are optional if not passing in an argument.
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echo $my_class->property; // => "public"
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echo $my_class->instanceProp; // => "An instance property"
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$my_class->myMethod(); // => "MyClass"
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$my_class->myMethod(); // => "MyClass"
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// Extend classes using "extends"
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class MyOtherClass extends MyClass{
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function printProtectedProperty(){
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echo $this->protprop;
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class MyOtherClass extends MyClass
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{
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function printProtectedProperty()
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{
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echo $this->protProp;
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}
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// Override a method
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function myMethod() {
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function myMethod()
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{
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parent::myMethod();
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print " > MyOtherClass";
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print ' > MyOtherClass';
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}
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}
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$my_other_class = new MyOtherClass("Instance prop");
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$my_other_class = new MyOtherClass('Instance prop');
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$my_other_class->printProtectedProperty(); // => Prints "protected"
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$my_other_class->myMethod(); // Prints "MyClass > MyOtherClass"
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$my_other_class->myMethod(); // Prints "MyClass > MyOtherClass"
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final class YouCannotExtendMe {
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final class YouCannotExtendMe
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{
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}
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// You can use "magic methods" to create getters and setters
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class MyMapClass {
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class MyMapClass
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{
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private $property;
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public function __get($key)
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@ -463,16 +480,19 @@ interface InterfaceTwo
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abstract class MyAbstractClass implements InterfaceOne
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{
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public $x = "doSomething";
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public $x = 'doSomething';
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}
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class MyConcreteClass extends MyAbstractClass implements InterfaceTwo
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{
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public function doSomething(){
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public function doSomething()
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{
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echo $x;
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}
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public function doSomethingElse(){
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echo "doSomethingElse";
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public function doSomethingElse()
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{
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echo 'doSomethingElse';
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}
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}
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@ -480,11 +500,14 @@ class MyConcreteClass extends MyAbstractClass implements InterfaceTwo
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// Classes can implement more than one interface
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class SomeOtherClass implements InterfaceOne, InterfaceTwo
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{
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public function doSomething(){
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echo "doSomething";
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public function doSomething()
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{
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echo 'doSomething';
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}
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public function doSomethingElse(){
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echo "doSomethingElse";
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public function doSomethingElse()
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{
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echo 'doSomethingElse';
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}
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}
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@ -493,12 +516,13 @@ class SomeOtherClass implements InterfaceOne, InterfaceTwo
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* Traits
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*/
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//Traits are available since PHP 5.4.0 and are declared using the trait keyword.
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// Traits are available since PHP 5.4.0 and are declared using the trait keyword.
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trait MyTrait {
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trait MyTrait
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{
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public function myTraitMethod()
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{
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print "I have MyTrait";
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print 'I have MyTrait';
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}
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}
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@ -566,3 +590,5 @@ Visit the [official PHP documentation](http://www.php.net/manual/) for reference
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If you're interested in up-to-date best practices, visit [PHP The Right Way](http://www.phptherightway.com/).
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If you're coming from a language with good package management, check out [Composer](http://getcomposer.org/).
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For common standards, visit the PHP Framework Interoperability Group's [PSR standards](https://github.com/php-fig/fig-standards).
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