diff options
Diffstat (limited to 'php.html.markdown')
| -rw-r--r-- | php.html.markdown | 89 |
1 files changed, 79 insertions, 10 deletions
diff --git a/php.html.markdown b/php.html.markdown index e81b88fd..2b1fe1dc 100644 --- a/php.html.markdown +++ b/php.html.markdown @@ -1,5 +1,5 @@ --- -language: php +language: PHP contributors: - ["Malcolm Fell", "http://emarref.net/"] - ["Trismegiste", "https://github.com/Trismegiste"] @@ -9,9 +9,9 @@ filename: learnphp.php This document describes PHP 5+. ```php -<?php // PHP code must be enclosed with <?php ? > tags +<?php // PHP code must be enclosed with <?php tags -// If your php file only contains PHP code, it is best practise +// If your php file only contains PHP code, it is best practice // to omit the php closing tag. // Two forward slashes start a one-line comment. @@ -31,7 +31,8 @@ echo "World\n"; // Prints "World" with a line break // (all statements must end with a semicolon) // Anything outside <?php tags is echoed automatically -?>Hello World Again! +?> +Hello World Again! <?php @@ -58,6 +59,9 @@ $float = 1.234; $float = 1.2e3; $float = 7E-10; +// Delete variable +unset($int1); + // Arithmetic $sum = 1 + 1; // 2 $difference = 2 - 1; // 1 @@ -68,7 +72,7 @@ $quotient = 2 / 1; // 2 $number = 0; $number += 1; // Increment $number by 1 echo $number++; // Prints 1 (increments after evaluation) -echo ++$number; // Prints 3 (increments before evalutation) +echo ++$number; // Prints 3 (increments before evaluation) $number /= $float; // Divide and assign the quotient to $number // Strings should be enclosed in single quotes; @@ -101,6 +105,21 @@ echo 'This string ' . 'is concatenated'; /******************************** + * Constants + */ + +// A constant is defined by using define() +// and can never be changed during runtime! + +// a valid constant name starts with a letter or underscore, +// followed by any number of letters, numbers, or underscores. +define("FOO", "something"); + +// access to a constant is possible by direct using the choosen name +echo 'This outputs '.FOO; + + +/******************************** * Arrays */ @@ -120,6 +139,11 @@ echo $associative['One']; // prints 1 $array = ['One', 'Two', 'Three']; echo $array[0]; // => "One" +// Add an element to the end of an array +$array[] = 'Four'; + +// Remove element from array +unset($array[3]); /******************************** * Output @@ -160,6 +184,11 @@ $y = 0; echo $x; // => 2 echo $z; // => 0 +// Dumps type and value of variable to stdout +var_dump($z); // prints int(0) + +// Prints variable to stdout in human-readable format +print_r($array); // prints: Array ( [0] => One [1] => Two [2] => Three ) /******************************** * Logic @@ -183,9 +212,17 @@ assert($c >= $d); // The following will only be true if the values match and are the same type. assert($c === $d); assert($a !== $d); -assert(1 == '1'); +assert(1 === '1'); assert(1 !== '1'); +// spaceship operator since PHP 7 +$a = 100; +$b = 1000; + +echo $a <=> $a; // 0 since they are equal +echo $a <=> $b; // -1 since $a < $b +echo $b <=> $a; // 1 since $b > $a + // Variables can be converted between types, depending on their usage. $integer = 1; @@ -235,6 +272,18 @@ if (false) { // ternary operator print (false ? 'Does not get printed' : 'Does'); +// ternary shortcut operator since PHP 5.3 +// equivalent of "$x ? $x : 'Does'"" +$x = false; +print($x ?: 'Does'); + +// null coalesce operator since php 7 +$a = null; +$b = 'Does print'; +echo $a ?? 'a is not set'; // prints 'a is not set' +echo $b ?? 'b is not set'; // prints 'Does print' + + $x = 0; if ($x === '0') { print 'Does not print'; @@ -424,6 +473,13 @@ class MyClass static $staticVar = 'static'; + // Static variables and their visibility + public static $publicStaticVar = 'publicStatic'; + // Accessible within the class only + private static $privateStaticVar = 'privateStatic'; + // Accessible from the class and subclasses + protected static $protectedStaticVar = 'protectedStatic'; + // Properties must declare their visibility public $property = 'public'; public $instanceProp; @@ -442,17 +498,26 @@ class MyClass print 'MyClass'; } + //final keyword would make a function unoverridable final function youCannotOverrideMe() { } +/* + * Declaring class properties or methods as static makes them accessible without + * needing an instantiation of the class. A property declared as static can not + * be accessed with an instantiated class object (though a static method can). + */ + public static function myStaticMethod() { print 'I am static'; } } +// Class constants can always be accessed statically echo MyClass::MY_CONST; // Outputs 'value'; + echo MyClass::$staticVar; // Outputs 'static'; MyClass::myStaticMethod(); // Outputs 'I am static'; @@ -634,10 +699,14 @@ $cls = new SomeOtherNamespace\MyClass(); ## More Information -Visit the [official PHP documentation](http://www.php.net/manual/) for reference and community input. +Visit the [official PHP documentation](http://www.php.net/manual/) for reference +and community input. -If you're interested in up-to-date best practices, visit [PHP The Right Way](http://www.phptherightway.com/). +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/). +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). +For common standards, visit the PHP Framework Interoperability Group's +[PSR standards](https://github.com/php-fig/fig-standards).
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