diff options
| -rw-r--r-- | php.html.markdown | 170 |
1 files changed, 98 insertions, 72 deletions
diff --git a/php.html.markdown b/php.html.markdown index b3c8f822..7db50136 100644 --- a/php.html.markdown +++ b/php.html.markdown @@ -10,6 +10,8 @@ This document describes PHP 5+. ```php <?php // PHP code must be enclosed with <?php ? > tags +// If your php file only contains PHP code, it is best practise to omit the php closing tag. + // Two forward slashes start a one-line comment. # So will a hash (aka pound symbol) but // is more common @@ -23,7 +25,7 @@ This document describes PHP 5+. print('Hello '); // Prints "Hello " with no line break // () are optional for print and echo -echo 'World\n'; // Prints "World" with a line break +echo "World\n"; // Prints "World" with a line break // (all statements must end with a semicolon) // Anything outside <?php tags is echoed automatically @@ -40,13 +42,13 @@ echo 'World\n'; // Prints "World" with a line break // followed by any number of letters, numbers, or underscores. // Boolean values are case-insensitive -$boolean = true; // or TRUE or True +$boolean = true; // or TRUE or True $boolean = false; // or FALSE or False // Integers -$int1 = 19; // => 19 -$int2 = -19; // => -19 -$int3 = 019; // => 15 (a leading 0 denotes an octal number) +$int1 = 19; // => 19 +$int2 = -19; // => -19 +$int3 = 019; // => 15 (a leading 0 denotes an octal number) $int4 = 0x0F; // => 15 (a leading 0x denotes a hex literal) // Floats (aka doubles) @@ -55,26 +57,26 @@ $float = 1.2e3; $float = 7E-10; // Arithmetic -$sum = 1 + 1; // 2 +$sum = 1 + 1; // 2 $difference = 2 - 1; // 1 -$product = 2 * 2; // 4 -$quotient = 2 / 1; // 2 +$product = 2 * 2; // 4 +$quotient = 2 / 1; // 2 // Shorthand arithmetic $number = 0; -$number += 1; // Add 1 to $number -echo $number++; // Prints 1 (increments after evaluation) -echo ++$number; // Prints 3 (increments before evalutation) +$number += 1; // Increment $number by 1 +echo $number++; // Prints 1 (increments after evaluation) +echo ++$number; // Prints 3 (increments before evalutation) $number /= $float; // Divide and assign the quotient to $number // Strings should be enclosed in single quotes; $sgl_quotes = '$String'; // => '$String' // Avoid using double quotes except to embed other variables -$dbl_quotes = "This is a $sgl_quotes."; // => 'This is a $String' +$dbl_quotes = "This is a $sgl_quotes."; // => 'This is a $String.' // Special characters are only escaped in double quotes -$escaped = "This contains a \t tab character."; +$escaped = "This contains a \t tab character."; $unescaped = 'This just contains a slash and a t: \t'; // Enclose a variable in curly braces if needed @@ -110,7 +112,7 @@ $associative = array('One' => 1, 'Two' => 2, 'Three' => 3); // PHP 5.4 introduced a new syntax $associative = ['One' => 1, 'Two' => 2, 'Three' => 3]; -echo $associative['One']; // prints "1" +echo $associative['One']; // prints 1 // List literals implicitly assign integer keys $array = ['One', 'Two', 'Three']; @@ -133,8 +135,8 @@ print 'Hello World!'; // So is print $paragraph = 'paragraph'; -echo 100; -echo $paragraph; +echo 100; // Echo scalar variables directly +echo $paragraph; // or variables // If short open tags are configured, or your PHP version is // 5.4.0 or greater, you can use the short echo syntax @@ -144,10 +146,11 @@ echo $paragraph; $x = 1; $y = 2; -$x = $y; // A now contains the same value sa $y +$x = $y; // $x now contains the same value as $y $z = &$y; -// $x now contains a reference to $y. Changing the value of -// $x will change the value of $y also, and vice-versa. +// $z now contains a reference to $y. Changing the value of +// $z will change the value of $y also, and vice-versa. +// $x will remain unchanged as the original value of $y echo $x; // => 2 echo $z; // => 2 @@ -216,7 +219,7 @@ if (true) { } if (false) { - print "I don't"; + print 'I don\'t'; } else { print 'I get printed'; } @@ -251,7 +254,7 @@ This is displayed otherwise. switch ($x) { case '0': print 'Switch does type coercion'; - break; // You must include a break, or you will fall through + break; // You must include a break, or you will fall through to cases 'two' and 'three' case 'two': case 'three': // Do something if $variable is either 'two' or 'three' @@ -276,16 +279,16 @@ do { echo "\n"; for ($x = 0; $x < 10; $x++) { - echo $x; // Will echo 0 - 9 -}// Prints "0123456789" + echo $x; +} // Prints "0123456789" echo "\n"; $wheels = ['bicycle' => 2, 'car' => 4]; // Foreach loops can iterate over arrays -foreach ($wheels as $wheel_count){ - echo "$wheel_count"; +foreach ($wheels as $wheel_count) { + echo $wheel_count; } // Prints "24" echo "\n"; @@ -303,9 +306,9 @@ while ($i < 5) { break; // Exit out of the while loop } echo $i++; -}// Prints "012" +} // Prints "012" -for($i = 0; $i < 5; $i++){ +for ($i = 0; $i < 5; $i++) { if ($i === 3) { continue; // Skip this iteration of the loop } @@ -318,7 +321,7 @@ for($i = 0; $i < 5; $i++){ */ // Define a function with "function": -function my_function() { +function my_function () { return 'Hello'; } @@ -327,7 +330,7 @@ echo my_function(); // => "Hello" // A valid function name starts with a letter or underscore, followed by any // number of letters, numbers, or underscores. -function add($x, $y = 1) { // $y is optional, and defaults to 2 +function add ($x, $y = 1) { // $y is optional and defaults to 1 $result = $x + $y; return $result; } @@ -339,7 +342,7 @@ echo add(4, 2); // => 6 // print $result; // Gives a warning. // Since PHP 5.3 you can declare anonymous functions; -$inc = function($x){ +$inc = function ($x) { return $x + 1; }; @@ -358,78 +361,92 @@ function bar ($x, $y) { } $bar = bar('A', 'B'); -$bar('C'); +$bar('C'); // Prints "A - B - C" // You can call named functions using strings $function_name = 'add'; echo $function_name(1, 2); // => 3 -// But, you should probably use anonymous functions instead. +// Useful for programatically determining which function to run. +// Alternatively, use call_user_func(callable $callback [, mixed $parameter [, mixed $... ]]); /******************************** * Classes */ -//Classes are defined with the class keyword +// Classes are defined with the class keyword + +class MyClass +{ + const MY_CONST = 'value'; // A constant + + static $staticVar = 'static'; -class MyClass { - const MY_CONST = 'value'; // A constant - static $staticVar = 'static'; - public $property = 'public'; // Properties must declare their visibility - private $privprop = 'private'; // Accessible within the class only - protected $protprop = 'protected'; // Accessible within the class and subclasses + // Properties must declare their visibility + public $property = 'public'; public $instanceProp; + protected $protProp = 'protected'; // Accessible within the class and subclasses + private $privProp = 'private'; // Accessible within the class only // Create a constructor with __construct - public function __construct($instanceProp){ + public function __construct($instanceProp) { // Access instance variables with $this $this->instanceProp = $instanceProp; } + // Methods are declared as functions inside a class - public function myMethod() { - print "MyClass"; + public function myMethod() + { + print 'MyClass'; } - final function youCannotOverrideMe() { + final function youCannotOverrideMe() + { } - public static function myStaticMethod() { - print "I am static"; + public static function myStaticMethod() + { + print 'I am static'; } } -echo MyClass::MY_CONST; // Outputs "value"; -echo MyClass::$staticVar; // Outputs 'static'; -MyClass::myStaticMethod(); // Outputs "I am static"; +echo MyClass::MY_CONST; // Outputs 'value'; +echo MyClass::$staticVar; // Outputs 'static'; +MyClass::myStaticMethod(); // Outputs 'I am static'; -// Access class members using ->. -$my_class = new MyClass("An instance property"); // The parentheses are optional. -echo $my_class->property; // => "public" +// Access class members using -> +$my_class = new MyClass('An instance property'); // The parentheses are optional if not passing in an argument. +echo $my_class->property; // => "public" echo $my_class->instanceProp; // => "An instance property" -$my_class->myMethod(); // => "MyClass" +$my_class->myMethod(); // => "MyClass" // Extend classes using "extends" -class MyOtherClass extends MyClass{ - function printProtectedProperty(){ - echo $this->protprop; +class MyOtherClass extends MyClass +{ + function printProtectedProperty() + { + echo $this->protProp; } // Override a method - function myMethod() { + function myMethod() + { parent::myMethod(); - print " > MyOtherClass"; + print ' > MyOtherClass'; } } -$my_other_class = new MyOtherClass("Instance prop"); +$my_other_class = new MyOtherClass('Instance prop'); $my_other_class->printProtectedProperty(); // => Prints "protected" -$my_other_class->myMethod(); // Prints "MyClass > MyOtherClass" +$my_other_class->myMethod(); // Prints "MyClass > MyOtherClass" -final class YouCannotExtendMe { +final class YouCannotExtendMe +{ } // You can use "magic methods" to create getters and setters -class MyMapClass { +class MyMapClass +{ private $property; public function __get($key) @@ -463,16 +480,19 @@ interface InterfaceTwo abstract class MyAbstractClass implements InterfaceOne { - public $x = "doSomething"; + public $x = 'doSomething'; } class MyConcreteClass extends MyAbstractClass implements InterfaceTwo { - public function doSomething(){ + public function doSomething() + { echo $x; } - public function doSomethingElse(){ - echo "doSomethingElse"; + + public function doSomethingElse() + { + echo 'doSomethingElse'; } } @@ -480,11 +500,14 @@ class MyConcreteClass extends MyAbstractClass implements InterfaceTwo // Classes can implement more than one interface class SomeOtherClass implements InterfaceOne, InterfaceTwo { - public function doSomething(){ - echo "doSomething"; + public function doSomething() + { + echo 'doSomething'; } - public function doSomethingElse(){ - echo "doSomethingElse"; + + public function doSomethingElse() + { + echo 'doSomethingElse'; } } @@ -493,12 +516,13 @@ class SomeOtherClass implements InterfaceOne, InterfaceTwo * Traits */ -//Traits are available since PHP 5.4.0 and are declared using the trait keyword. +// Traits are available since PHP 5.4.0 and are declared using the trait keyword. -trait MyTrait { +trait MyTrait +{ public function myTraitMethod() { - print "I have MyTrait"; + print 'I have MyTrait'; } } @@ -566,3 +590,5 @@ Visit the [official PHP documentation](http://www.php.net/manual/) for reference If you're interested in up-to-date best practices, visit [PHP The Right Way](http://www.phptherightway.com/). If you're coming from a language with good package management, check out [Composer](http://getcomposer.org/). + +For common standards, visit the PHP Framework Interoperability Group's [PSR standards](https://github.com/php-fig/fig-standards). |