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diff --git a/ja-jp/php.html.markdown b/ja-jp/php.html.markdown new file mode 100644 index 00000000..3831e220 --- /dev/null +++ b/ja-jp/php.html.markdown @@ -0,0 +1,767 @@ +--- +language: PHP +contributors: + - ["Malcolm Fell", "http://emarref.net/"] + - ["Trismegiste", "https://github.com/Trismegiste"] +translators: + - ["Kazushige Tominaga", "https://github.com/kazu9su"] +filename: learnphp.php +--- + +このドキュメントでは、 PHP 5+ について説明します。 + +```php +<?php // PHPのコードは、<?php タグで囲む必要があります。 + +// もしあなたのphpファイルがPHPのみで構成される場合、それがベストプラクティスです。 +// 意図しない出力を防ぐために、phpの閉じタグは省略するのがベストプラクティスです。 +// Two forward slashes start a one-line comment. + +# So will a hash (aka pound symbol) but // is more common + +/* + Surrounding text in slash-asterisk and asterisk-slash + makes it a multi-line comment. +*/ + +// Use "echo" or "print" to print output +print('Hello '); // Prints "Hello " with no line break + +// () are optional for print and echo +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! +<?php + + +/************************************ + * Types & Variables + */ + +// Variables begin with the $ symbol. +// A valid variable name starts with a letter or underscore, +// followed by any number of letters, numbers, or underscores. + +// Boolean values are case-insensitive +$boolean = true; // or TRUE or True +$boolean = false; // or FALSE or False + +// Integers +$int1 = 12; // => 12 +$int2 = -12; // => -12 +$int3 = 012; // => 10 (a leading 0 denotes an octal number) +$int4 = 0x0F; // => 15 (a leading 0x denotes a hex literal) + +// Floats (aka doubles) +$float = 1.234; +$float = 1.2e3; +$float = 7E-10; + +// Delete variable +unset($int1); + +// Arithmetic +$sum = 1 + 1; // 2 +$difference = 2 - 1; // 1 +$product = 2 * 2; // 4 +$quotient = 2 / 1; // 2 + +// Shorthand arithmetic +$number = 0; +$number += 1; // Increment $number by 1 +echo $number++; // Prints 1 (increments after evaluation) +echo ++$number; // Prints 3 (increments before evaluation) +$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 $String.' + +// Special characters are only escaped in double quotes +$escaped = "This contains a \t tab character."; +$unescaped = 'This just contains a slash and a t: \t'; + +// Enclose a variable in curly braces if needed +$money = "I have $${number} in the bank."; + +// Since PHP 5.3, nowdocs can be used for uninterpolated multi-liners +$nowdoc = <<<'END' +Multi line +string +END; + +// Heredocs will do string interpolation +$heredoc = <<<END +Multi line +$sgl_quotes +END; + +// String concatenation is done with . +echo 'This string ' . 'is concatenated'; + +// Strings can be passed in as parameters to echo +echo 'Multiple', 'Parameters', 'Valid'; + +/******************************** + * Constants + */ + +// A constant is defined by using define() +// and can never be changed during runtime! + +// a valid constant name starts with a letter or underscore, +// followed by any number of letters, numbers, or underscores. +define("FOO", "something"); + +// access to a constant is possible by direct using the choosen name +echo 'This outputs '.FOO; + + +/******************************** + * Arrays + */ + +// All arrays in PHP are associative arrays (hashmaps), + +// Associative arrays, known as hashmaps in some languages. + +// Works with all PHP versions +$associative = array('One' => 1, 'Two' => 2, 'Three' => 3); + +// PHP 5.4 introduced a new syntax +$associative = ['One' => 1, 'Two' => 2, 'Three' => 3]; + +echo $associative['One']; // prints 1 + +// List literals implicitly assign integer keys +$array = ['One', 'Two', 'Three']; +echo $array[0]; // => "One" + +// Add an element to the end of an array +$array[] = 'Four'; +// or +array_push($array, 'Five'); + +// Remove element from array +unset($array[3]); + +/******************************** + * Output + */ + +echo('Hello World!'); +// Prints Hello World! to stdout. +// Stdout is the web page if running in a browser. + +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 + +$paragraph = '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 +?> +<p><?= $paragraph ?></p> +<?php + +$x = 1; +$y = 2; +$x = $y; // $x now contains the same value as $y +$z = &$y; +// $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 $z; // => 2 +$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($array); // prints: Array ( [0] => One [1] => Two [2] => Three ) + +/******************************** + * Logic + */ +$a = 0; +$b = '0'; +$c = '1'; +$d = '1'; + +// assert throws a warning if its argument is not true + +// These comparisons will always be true, even if the types aren't the same. +assert($a == $b); // equality +assert($c != $a); // inequality +assert($c <> $a); // alternative inequality +assert($a < $c); +assert($c > $b); +assert($a <= $b); +assert($c >= $d); + +// The following will only be true if the values match and are the same type. +assert($c === $d); +assert($a !== $d); +assert(1 === '1'); +assert(1 !== '1'); + +// spaceship operator since PHP 7 +$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; +echo $integer + $integer; // => 2 + +$string = '1'; +echo $string + $string; // => 2 (strings are coerced to integers) + +$string = 'one'; +echo $string + $string; // => 0 +// Outputs 0 because the + operator cannot cast the string 'one' to a number + +// Type casting can be used to treat a variable as another type + +$boolean = (boolean) 1; // => true + +$zero = 0; +$boolean = (boolean) $zero; // => false + +// There are also dedicated functions for casting most types +$integer = 5; +$string = strval($integer); + +$var = null; // Null value + + +/******************************** + * Control Structures + */ + +if (true) { + print 'I get printed'; +} + +if (false) { + print 'I don\'t'; +} else { + print 'I get printed'; +} + +if (false) { + print 'Does not get printed'; +} elseif(true) { + print 'Does'; +} + +// ternary operator +print (false ? 'Does not get printed' : 'Does'); + +// ternary shortcut operator since PHP 5.3 +// equivalent of "$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 ($x === '0') { + print 'Does not print'; +} elseif($x == '1') { + print 'Does not print'; +} else { + print 'Does print'; +} + + + +// This alternative syntax is useful for templates: +?> + +<?php if ($x): ?> +This is displayed if the test is truthy. +<?php else: ?> +This is displayed otherwise. +<?php endif; ?> + +<?php + +// Use switch to save some logic. +switch ($x) { + case '0': + print 'Switch does type coercion'; + break; // You must include a break, or you will fall through + // to cases 'two' and 'three' + case 'two': + case 'three': + // Do something if $variable is either 'two' or 'three' + break; + default: + // Do something by default +} + +// While, do...while and for loops are probably familiar +$i = 0; +while ($i < 5) { + echo $i++; +}; // Prints "01234" + +echo "\n"; + +$i = 0; +do { + echo $i++; +} while ($i < 5); // Prints "01234" + +echo "\n"; + +for ($x = 0; $x < 10; $x++) { + echo $x; +} // Prints "0123456789" + +echo "\n"; + +$wheels = ['bicycle' => 2, 'car' => 4]; + +// Foreach loops can iterate over arrays +foreach ($wheels as $wheel_count) { + echo $wheel_count; +} // Prints "24" + +echo "\n"; + +// You can iterate over the keys as well as the values +foreach ($wheels as $vehicle => $wheel_count) { + echo "A $vehicle has $wheel_count wheels"; +} + +echo "\n"; + +$i = 0; +while ($i < 5) { + if ($i === 3) { + break; // Exit out of the while loop + } + echo $i++; +} // Prints "012" + +for ($i = 0; $i < 5; $i++) { + if ($i === 3) { + continue; // Skip this iteration of the loop + } + echo $i; +} // Prints "0124" + + +/******************************** + * Functions + */ + +// Define a function with "function": +function my_function () { + return 'Hello'; +} + +echo my_function(); // => "Hello" + +// A valid function name starts with a letter or underscore, followed by any +// number of letters, numbers, or underscores. + +function add ($x, $y = 1) { // $y is optional and defaults to 1 + $result = $x + $y; + return $result; +} + +echo add(4); // => 5 +echo add(4, 2); // => 6 + +// $result is not accessible outside the function +// print $result; // Gives a warning. + +// Since PHP 5.3 you can declare anonymous functions; +$inc = function ($x) { + return $x + 1; +}; + +echo $inc(2); // => 3 + +function foo ($x, $y, $z) { + echo "$x - $y - $z"; +} + +// Functions can return functions +function bar ($x, $y) { + // Use 'use' to bring in outside variables + return function ($z) use ($x, $y) { + foo($x, $y, $z); + }; +} + +$bar = bar('A', 'B'); +$bar('C'); // Prints "A - B - C" + +// You can call named functions using strings +$function_name = 'add'; +echo $function_name(1, 2); // => 3 +// Useful for programatically determining which function to run. +// Or, use call_user_func(callable $callback [, $parameter [, ... ]]); + + +// You can get the all the parameters passed to a function +function parameters() { + $numargs = func_num_args(); + if ($numargs > 0) { + echo func_get_arg(0) . ' | '; + } + $args_array = func_get_args(); + foreach ($args_array as $key => $arg) { + echo $key . ' - ' . $arg . ' | '; + } +} + +parameters('Hello', 'World'); // Hello | 0 - Hello | 1 - World | + +/******************************** + * Includes + */ + +<?php +// PHP within included files must also begin with a PHP open tag. + +include 'my-file.php'; +// The code in my-file.php is now available in the current scope. +// If the file cannot be included (e.g. file not found), a warning is emitted. + +include_once 'my-file.php'; +// If the code in my-file.php has been included elsewhere, it will +// not be included again. This prevents multiple class declaration errors + +require 'my-file.php'; +require_once 'my-file.php'; +// Same as include(), except require() will cause a fatal error if the +// file cannot be included. + +// Contents of my-include.php: +<?php + +return 'Anything you like.'; +// End file + +// Includes and requires may also return a value. +$value = include 'my-include.php'; + +// Files are included based on the file path given or, if none is given, +// the include_path configuration directive. If the file isn't found in +// the include_path, include will finally check in the calling script's +// own directory and the current working directory before failing. +/* */ + +/******************************** + * Classes + */ + +// Classes are defined with the class keyword + +class MyClass +{ + const MY_CONST = 'value'; // A constant + + 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; + protected $prot = 'protected'; // Accessible from the class and subclasses + private $priv = 'private'; // Accessible within the class only + + // Create a constructor with __construct + public function __construct($instanceProp) { + // Access instance variables with $this + $this->instanceProp = $instanceProp; + } + + // Methods are declared as functions inside a class + public function myMethod() + { + print 'MyClass'; + } + + //final keyword would make a function unoverridable + final function youCannotOverrideMe() + { + } + +/* + * Declaring class properties or methods as static makes them accessible without + * needing an instantiation of the class. A property declared as static can not + * be accessed with an instantiated class object (though a static method can). + */ + + public static function myStaticMethod() + { + print 'I am static'; + } +} + +// Class constants can always be accessed statically +echo MyClass::MY_CONST; // Outputs 'value'; + +echo MyClass::$staticVar; // Outputs 'static'; +MyClass::myStaticMethod(); // Outputs 'I am static'; + +// Instantiate classes using new +$my_class = new MyClass('An instance property'); +// The parentheses are optional if not passing in an argument. + +// Access class members using -> +echo $my_class->property; // => "public" +echo $my_class->instanceProp; // => "An instance property" +$my_class->myMethod(); // => "MyClass" + + +// Extend classes using "extends" +class MyOtherClass extends MyClass +{ + function printProtectedProperty() + { + echo $this->prot; + } + + // Override a method + function myMethod() + { + parent::myMethod(); + print ' > MyOtherClass'; + } +} + +$my_other_class = new MyOtherClass('Instance prop'); +$my_other_class->printProtectedProperty(); // => Prints "protected" +$my_other_class->myMethod(); // Prints "MyClass > MyOtherClass" + +final class YouCannotExtendMe +{ +} + +// You can use "magic methods" to create getters and setters +class MyMapClass +{ + private $property; + + public function __get($key) + { + return $this->$key; + } + + public function __set($key, $value) + { + $this->$key = $value; + } +} + +$x = new MyMapClass(); +echo $x->property; // Will use the __get() method +$x->property = 'Something'; // Will use the __set() method + +// Classes can be abstract (using the abstract keyword) or +// implement interfaces (using the implements keyword). +// An interface is declared with the interface keyword. + +interface InterfaceOne +{ + public function doSomething(); +} + +interface InterfaceTwo +{ + public function doSomethingElse(); +} + +// interfaces can be extended +interface InterfaceThree extends InterfaceTwo +{ + public function doAnotherContract(); +} + +abstract class MyAbstractClass implements InterfaceOne +{ + public $x = 'doSomething'; +} + +class MyConcreteClass extends MyAbstractClass implements InterfaceTwo +{ + public function doSomething() + { + echo $x; + } + + public function doSomethingElse() + { + echo 'doSomethingElse'; + } +} + + +// Classes can implement more than one interface +class SomeOtherClass implements InterfaceOne, InterfaceTwo +{ + public function doSomething() + { + echo 'doSomething'; + } + + public function doSomethingElse() + { + echo 'doSomethingElse'; + } +} + + +/******************************** + * Traits + */ + +// Traits are available from PHP 5.4.0 and are declared using "trait" + +trait MyTrait +{ + public function myTraitMethod() + { + print 'I have MyTrait'; + } +} + +class MyTraitfulClass +{ + use MyTrait; +} + +$cls = new MyTraitfulClass(); +$cls->myTraitMethod(); // Prints "I have MyTrait" + + +/******************************** + * Namespaces + */ + +// This section is separate, because a namespace declaration +// must be the first statement in a file. Let's pretend that is not the case + +<?php + +// By default, classes exist in the global namespace, and can +// be explicitly called with a backslash. + +$cls = new \MyClass(); + + + +// Set the namespace for a file +namespace My\Namespace; + +class MyClass +{ +} + +// (from another file) +$cls = new My\Namespace\MyClass; + +//Or from within another namespace. +namespace My\Other\Namespace; + +use My\Namespace\MyClass; + +$cls = new MyClass(); + +// Or you can alias the namespace; + +namespace My\Other\Namespace; + +use My\Namespace as SomeOtherNamespace; + +$cls = new SomeOtherNamespace\MyClass(); + +/********************** +* Error Handling +* +*/ + +// Simple error handling can be done with try catch block + +try { + // Do something +} catch ( Exception $e) { + // Handle exception +} + +// When using try catch blocks in a namespaced enviroment use the following + +try { + // Do something +} catch (\Exception $e) { + // Handle exception +} + +// Custom exceptions + +class MyException extends Exception {} + +try { + + $condition = true; + + if ($condition) { + throw new MyException('Something just happend'); + } + +} catch (MyException $e) { + // Handle my exception +} + +``` + +## More Information + +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 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). |