diff options
Diffstat (limited to 'php.html.markdown')
| -rw-r--r-- | php.html.markdown | 86 |
1 files changed, 58 insertions, 28 deletions
diff --git a/php.html.markdown b/php.html.markdown index cddba644..753f6ab1 100644 --- a/php.html.markdown +++ b/php.html.markdown @@ -47,8 +47,8 @@ $integer = 0123; // octal number (equivalent to 83 decimal) $integer = 0x1A; // hexadecimal number (equivalent to 26 decimal) // Floats (aka doubles) -$float = 1.234; -$float = 1.2e3; +$float = 1.234; +$float = 1.2e3; $float = 7E-10; // Arithmetic @@ -87,7 +87,7 @@ $sgl_quotes END; // Nowdoc syntax is available in PHP 5.3.0 // Manipulation -$concatenated = $sgl_quotes + $dbl_quotes; +$concatenated = $sgl_quotes . $dbl_quotes; ``` ### Compound @@ -119,6 +119,8 @@ print('Hello World!'); // The same as echo // echo is actually a language construct, so you can drop the parentheses. echo 'Hello World!'; +print 'Hello World!'; // So is print + echo 100; echo $variable; echo function_result(); @@ -135,12 +137,12 @@ echo function_result(); ```php <?php -$a = 1; -$b = 2; -$a = $b; // A now contains the same value sa $b -$a =& $b; -// A now contains a reference to $b. Changing the value of -// $a will change the value of $b also, and vice-versa. +$x = 1; +$y = 2; +$x = $y; // A now contains the same value sa $y +$x = &$y; +// $x now contains a reference to $y. Changing the value of +// $x will change the value of $y also, and vice-versa. ``` ### Comparison @@ -148,15 +150,20 @@ $a =& $b; ```php <?php +// These comparisons will always be true, even if the types aren't the same. $a == $b // TRUE if $a is equal to $b after type juggling. -$a === $b // TRUE if $a is equal to $b, and they are of the same type. $a != $b // TRUE if $a is not equal to $b after type juggling. $a <> $b // TRUE if $a is not equal to $b after type juggling. -$a !== $b // TRUE if $a is not equal to $b, or they are not of the same type. $a < $b // TRUE if $a is strictly less than $b. $a > $b // TRUE if $a is strictly greater than $b. $a <= $b // TRUE if $a is less than or equal to $b. $a >= $b // TRUE if $a is greater than or equal to $b. + +// The following will only be true if the values match and are the same type. +$a === $b // TRUE if $a is equal to $b, and they are of the same type. +$a !== $b // TRUE if $a is not equal to $b, or they are not of the same type. +1 == '1' // TRUE +1 === '1' // FALSE ``` ## [Type Juggling](http://www.php.net/manual/en/language.types.type-juggling.php) @@ -176,7 +183,11 @@ echo $string + $string; $string = 'one'; echo $string + $string; // Outputs 0 because the + operator cannot cast the string 'one' to a number +``` +Type casting can be used to treat a variable as another type temporarily by using cast operators in parentheses. + +```php $boolean = (boolean) $integer; // $boolean is true $zero = 0; @@ -222,9 +233,9 @@ if (/* test */) { ?> <?php if (/* test */): ?> -<!-- Do something that isn't PHP --> +This is displayed if the test is truthy. <?php else: ?> -<!-- Do something default --> +This is displayed otherwise. <?php endif; ?> ``` @@ -278,7 +289,6 @@ while ($i < 5) { if ($i == 3) { break; // Exit out of the while loop and continue. } - echo $i++; } @@ -288,7 +298,6 @@ while ($i < 5) { if ($i == 3) { continue; // Skip this iteration of the loop } - echo $i++; } ``` @@ -325,8 +334,8 @@ number of letters, numbers, or underscores. There are three ways to declare func ```php <?php -function my_function_name ($arg_1, $arg_2) { // $arg_1 and $arg_2 are required - // Do something with $arg_1 and $arg_2; +function my_function_name ($arg_1, $arg_2) { + // $arg_1 and $arg_2 are required } // Functions may be nested to limit scope @@ -335,7 +344,25 @@ function outer_function ($arg_1 = null) { // $arg_1 is optional } } -// inner_function() does not exist and cannot be called until outer_function() is called +// inner_function() does not exist and cannot be called until +// outer_function() is called +``` + +This enables [currying](http://en.wikipedia.org/wiki/Currying) in PHP. + +```php +function foo ($x, $y, $z) { + echo "$x - $y - $z"; +} + +function bar ($x, $y) { + return function ($z) use ($x, $y) { + foo($x, $y, $z); + }; +} + +$bar = bar('A', 'B'); +$bar('C'); ``` ### [Variable](http://www.php.net/manual/en/functions.variable-functions.php) @@ -355,7 +382,11 @@ Similar to variable functions, functions may be anonymous. ```php <?php -my_function(function () { +function my_function($callback) { + $callback('My argument'); +} + +my_function(function ($my_argument) { // do something }); @@ -395,13 +426,11 @@ methods if they belong to a class. class MyClass { function myFunction() { } - - function function youCannotOverrideMe() - { + + final function youCannotOverrideMe() { } - - public static function myStaticMethod() - { + + public static function myStaticMethod() { } } @@ -421,12 +450,12 @@ PHP offers some [magic methods](http://www.php.net/manual/en/language.oop5.magic class MyClass { private $property; - + public function __get($key) { return $this->$key; } - + public function __set($key, $value) { $this->$key = $value; @@ -438,7 +467,8 @@ echo $x->property; // Will use the __get() method $x->property = 'Something'; // Will use the __set() method ``` -Classes can be abstract (using the ```abstract``` keyword), extend other classes (using the ```extends``` keyword) and implement interfaces (using the ```implements``` keyword). An interface is declared with the ```interface``` keyword. +Classes can be abstract (using the ```abstract``` keyword), extend other classes (using the ```extends``` keyword) and +implement interfaces (using the ```implements``` keyword). An interface is declared with the ```interface``` keyword. ```php <?php |