973 lines
15 KiB
Markdown
973 lines
15 KiB
Markdown
PHP 备忘清单
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===
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这份 [PHP](https://www.php.net/manual/zh/index.php) 备忘单为快速查找最常用代码的正确语法提供了参考
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入门
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------
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### hello.php
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```php
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<?php // 以 PHP 开放标签开头
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echo "Hello World\n";
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print("Hello jaywcjlove.github.io");
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?>
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```
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PHP 运行命令
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```shell
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$ php hello.php
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```
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### 变量 Variables
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```php
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$boolean1 = true;
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$boolean2 = True;
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$int = 12;
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$float = 3.1415926;
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unset($float); // 删除变量
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$str1 = "How are you?";
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$str2 = 'Fine, thanks';
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```
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查看: [Types](#php-类型)
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### 字符串 Strings
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```php
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$url = "jaywcjlove.github.io";
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echo "I'm learning PHP at $url";
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// 连接字符串
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echo "I'm learning PHP at " . $url;
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$hello = "Hello, ";
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$hello .= "World!";
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echo $hello; # => Hello, World!
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```
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查看: [Strings](#php-字符串)
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### 数组 Arrays
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```php
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$num = [1, 3, 5, 7, 9];
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$num[5] = 11;
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unset($num[2]); // 删除变量
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print_r($num); # => 1 3 7 9 11
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echo count($num); # => 5
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```
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查看: [Arrays](#php-数组)
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### 运算符 Operators
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```php
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$x = 1;
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$y = 2;
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$sum = $x + $y;
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echo $sum; # => 3
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```
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查看: [Operators](#php-运算符)
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### Include
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<!--rehype:wrap-class=row-span-3-->
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#### vars.php
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```php
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<?php // 以 PHP 开放标签开头。
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$fruit = 'apple';
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echo "I was imported";
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return 'Anything you like.';
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?>
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```
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#### test.php
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```php
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<?php
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include 'vars.php';
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echo $fruit . "\n"; # => apple
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/* 与 include 相同，
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如果不能包含则导致错误*/
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require 'vars.php';
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// 也有效
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include('vars.php');
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require('vars.php');
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// 通过 HTTP 包含
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include 'http://x.com/file.php';
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// 包含和返回语句
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$result = include 'vars.php';
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echo $result; # => Anything you like.
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?>
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```
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### 功能 Functions
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```php
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function add($num1, $num2 = 1) {
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return $num1 + $num2;
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}
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echo add(10); # => 11
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echo add(10, 5); # => 15
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```
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查看: [Functions](#php-函数)
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### 注释 Comments
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```php
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# 这是一个单行 shell 样式的注释
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// 这是一行 c++ 风格的注释
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/* 这是一个多行注释
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另一行注释 */
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```
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### 常数 Constants
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```php
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const MY_CONST = "hello";
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echo MY_CONST; # => hello
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# => MY_CONST is: hello
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echo 'MY_CONST is: ' . MY_CONST;
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```
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### 类 Classes
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```php
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class Student {
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public function __construct($name) {
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$this->name = $name;
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}
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}
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$alex = new Student("Alex");
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```
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查看: [Classes](#php-类)
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PHP 类型
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------
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### 布尔值 Boolean
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<!--rehype:wrap-class=row-span-2-->
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```php
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$boolean1 = true;
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$boolean2 = TRUE;
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$boolean3 = false;
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$boolean4 = FALSE;
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$boolean5 = (boolean) 1; # => true
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$boolean6 = (boolean) 0; # => false
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```
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布尔值不区分大小写
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### 整数 Integer
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<!--rehype:wrap-class=row-span-2-->
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```php
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$int1 = 28; # => 28
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$int2 = -32; # => -32
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$int3 = 012; # => 10 (octal)
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$int4 = 0x0F; # => 15 (hex)
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$int5 = 0b101; # => 5 (binary)
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# => 2000100000 (decimal, PHP 7.4.0)
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$int6 = 2_000_100_000;
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```
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另见: [Integers](https://www.php.net/manual/en/language.types.integer.php)
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### 字符串 Strings
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```php
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echo 'this is a simple string';
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```
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查看: [Strings](#php-字符串)
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### 数组 Arrays
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```php
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$arr = array("hello", "world", "!");
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```
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查看: [Arrays](#php-数组)
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### 浮点数 Float (Double)
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```php
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$float1 = 1.234;
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$float2 = 1.2e7;
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$float3 = 7E-10;
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$float4 = 1_234.567; // as of PHP 7.4.0
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var_dump($float4); // float(1234.567)
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$float5 = 1 + "10.5"; # => 11.5
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$float6 = 1 + "-1.3e3"; # => -1299
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```
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### Null
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```php
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$a = null;
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$b = 'Hello php!';
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echo $a ?? 'a is unset'; # => a is unset
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echo $b ?? 'b is unset'; # => Hello php
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$a = array();
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$a == null # => true
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$a === null # => false
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is_null($a) # => false
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```
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### 可迭代对象 Iterables
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```php
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function bar(): iterable {
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return [1, 2, 3];
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}
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function gen(): iterable {
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yield 1;
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yield 2;
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yield 3;
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}
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foreach (bar() as $value) {
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echo $value; # => 123
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}
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```
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PHP 字符串
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------
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### 字符串 String
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```php
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# => '$String'
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$sgl_quotes = '$String';
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# => 'This is a $String.'
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$dbl_quotes = "This is a $sgl_quotes.";
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# => a tab character.
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$escaped = "a \t tab character.";
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# => a slash and a t: \t
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$unescaped = 'a slash and a t: \t';
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```
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### 多行 Multi-line
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```php
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$str = "foo";
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// 未插值的多行
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$nowdoc = <<<'END'
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Multi line string
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$str
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END;
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// 将执行字符串插值
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$heredoc = <<<END
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Multi line
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$str
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END;
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```
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### 操作 Manipulation
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```php
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$s = "Hello Phper";
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echo strlen($s); # => 11
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echo substr($s, 0, 3); # => Hel
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echo substr($s, 1); # => ello Phper
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echo substr($s, -4, 3);# => hpe
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echo strtoupper($s); # => HELLO PHPER
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echo strtolower($s); # => hello phper
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echo strpos($s, "l"); # => 2
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var_dump(strpos($s, "L")); # => false
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```
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另见: [字符串函数](https://www.php.net/manual/en/ref.strings.php)
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PHP 数组
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------
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### 定义
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<!--rehype:wrap-class=row-span-2-->
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```php
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$a1 = ["hello", "world", "!"]
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$a2 = array("hello", "world", "!");
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$a3 = explode(",", "apple,pear,peach");
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```
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#### 混合 int 和 string 键
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```php
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$array = array(
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"foo" => "bar",
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"bar" => "foo",
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100 => -100,
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-100 => 100,
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);
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var_dump($array);
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```
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#### 短数组语法
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```php
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$array = [
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"foo" => "bar",
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"bar" => "foo",
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];
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```
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### 多阵列
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```php
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$multiArray = [
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[1, 2, 3],
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[4, 5, 6],
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[7, 8, 9],
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];
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print_r($multiArray[0][0]) # => 1
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print_r($multiArray[0][1]) # => 2
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print_r($multiArray[0][2]) # => 3
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```
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### 多类型
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<!--rehype:wrap-class=row-span-2-->
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```php
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$array = array(
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"foo" => "bar",
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42 => 24,
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"multi" => array(
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"dim" => array(
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"a" => "foo"
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)
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)
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);
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# => string(3) "bar"
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var_dump($array["foo"]);
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# => int(24)
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var_dump($array[42]);
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# => string(3) "foo"
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var_dump($array["multi"]["dim"]["a"]);
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```
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### 操作
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```php
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$arr = array(5 => 1, 12 => 2);
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$arr[] = 56; // 附加
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$arr["x"] = 42; // 用键添加
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sort($arr); // 排序
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unset($arr[5]); // 消除
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unset($arr); // 移除所有
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```
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查看: [数组函数](https://www.php.net/manual/en/ref.array.php)
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### 索引迭代
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```php
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$array = array('a', 'b', 'c');
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$count = count($array);
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for ($i = 0; $i < $count; $i++) {
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echo "i:{$i}, v:{$array[$i]}\n";
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}
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```
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### 价值迭代
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```php
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$colors = array('red', 'blue', 'green');
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foreach ($colors as $color) {
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echo "Do you like $color?\n";
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}
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```
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### 关键迭代
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```php
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$arr = ["foo" => "bar", "bar" => "foo"];
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foreach ( $arr as $key => $value )
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{
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echo "key: " . $key . "\n";
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echo "val: {$arr[$key]}\n";
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}
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```
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### 串联阵列
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```php
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$a = [1, 2];
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$b = [3, 4];
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// PHP 7.4 以后
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# => [1, 2, 3, 4]
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$result = [...$a, ...$b];
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```
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### Into 函数
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```php
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$array = [1, 2];
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function foo(int $a, int $b) {
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echo $a; # => 1
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echo $b; # => 2
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}
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foo(...$array);
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```
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### Splat运算符
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```php
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function foo($first, ...$other) {
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var_dump($first); # => a
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var_dump($other); # => ['b', 'c']
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}
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foo('a', 'b', 'c' /*, ...*/ );
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// 或
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function foo($first, string ...$other){}
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```
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PHP 运算符
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-------
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### 算术
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:- | -
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:- | -
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`+` | 添加
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`-` | 减法
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`*` | 乘法
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`/` | 分配
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`%` | 取模
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`**` | 求幂
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### 分配
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:- | -
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:- | -
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`a += b` | 如同 `a = a + b`
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`a -= b` | 如同 `a = a – b`
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`a *= b` | 如同 `a = a * b`
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`a /= b` | 如同 `a = a / b`
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`a %= b` | 如同 `a = a % b`
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### 比较
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:- | -
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:- | -
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`==` | 平等的
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`===` | 完全相同的
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`!=` | 不相等
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`<>` | 不相等
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`!==` | 不相同
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`<` | 少于
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`>` | 比...更棒
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`<=` | 小于或等于
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`>=` | 大于或等于
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`<=>` | 小于/等于/大于
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### 逻辑的
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:- | -
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:- | -
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`and` | 和
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`or` | 或者
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`xor` | 独家或
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`!` | 不是
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`&&` | 和
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`\|\|` | 或者
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### 算术
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```php
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// 算术
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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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// 速记算术
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$num = 0;
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$num += 1; // 将 $num 增加 1
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echo $num++; // 打印 1（评估后的增量）
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echo ++$num; // 打印 3（评估前的增量）
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$num /= $float; // 将商除并分配给 $num
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```
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### 按位
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:- | -
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:- | -
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`&` | 和
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`|` | 或（包括或）
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`^` | 异或（异或）
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`~` | 不是
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`<<` | 左移
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`>>` | 右移
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PHP 条件
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------
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### If elseif else
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```php
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$a = 10;
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$b = 20;
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if ($a > $b) {
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echo "a is bigger than b";
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} elseif ($a == $b) {
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echo "a is equal to b";
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} else {
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echo "a is smaller than b";
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}
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```
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### Switch
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```php
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$x = 0;
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switch ($x) {
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case '0':
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print "it's zero";
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break;
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case 'two':
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case 'three':
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// do something
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break;
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default:
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// do something
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}
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```
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### 三元运算符
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```php
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# => Does
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print (false ? 'Not' : 'Does');
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$x = false;
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# => Does
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print($x ?: 'Does');
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$a = null;
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$b = 'Does print';
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# => a is unsert
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echo $a ?? 'a is unset';
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# => print
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echo $b ?? 'b is unset';
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```
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### 匹配
|
||
|
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```php
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$statusCode = 500;
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$message = match($statusCode) {
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200, 300 => null,
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400 => '未找到',
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500 => '服务器错误',
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default => '已知状态码',
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};
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echo $message; # => 服务器错误
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```
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|
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查看: [Match](https://www.php.net/manual/en/control-structures.match.php)
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|
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### 匹配表达式
|
||
|
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```php
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$age = 23;
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$result = match (true) {
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$age >= 65 => 'senior',
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$age >= 25 => 'adult',
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$age >= 18 => 'young adult',
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default => 'kid',
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};
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echo $result; # => young adult
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```
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|
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PHP 循环
|
||
------
|
||
|
||
### while 循环
|
||
|
||
```php
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||
$i = 1;
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# => 12345
|
||
while ($i <= 5) {
|
||
echo $i++;
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}
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```
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|
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### do while 循环
|
||
|
||
```php
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||
$i = 1;
|
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# => 12345
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||
do {
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echo $i++;
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} while ($i <= 5);
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```
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|
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### for i 循环
|
||
|
||
```php
|
||
# => 12345
|
||
for ($i = 1; $i <= 5; $i++) {
|
||
echo $i;
|
||
}
|
||
```
|
||
|
||
### break 跳出循环
|
||
|
||
```php
|
||
# => 123
|
||
for ($i = 1; $i <= 5; $i++) {
|
||
if ($i === 4) {
|
||
break;
|
||
}
|
||
echo $i;
|
||
}
|
||
```
|
||
|
||
### continue 继续
|
||
|
||
```php
|
||
# => 1235
|
||
for ($i = 1; $i <= 5; $i++) {
|
||
if ($i === 4) {
|
||
continue;
|
||
}
|
||
echo $i;
|
||
}
|
||
```
|
||
|
||
### foreach 循环
|
||
|
||
```php
|
||
$a = ['foo' => 1, 'bar' => 2];
|
||
# => 12
|
||
foreach ($a as $k) {
|
||
echo $k;
|
||
}
|
||
```
|
||
|
||
查看: [Array iteration](#关键迭代)
|
||
|
||
PHP 函数
|
||
------
|
||
|
||
### 返回值
|
||
|
||
```php
|
||
function square($x)
|
||
{
|
||
return $x * $x;
|
||
}
|
||
echo square(4); # => 16
|
||
```
|
||
|
||
### 返回类型
|
||
|
||
```php
|
||
// 基本返回类型声明
|
||
function sum($a, $b): float {/*...*/}
|
||
function get_item(): string {/*...*/}
|
||
class C {}
|
||
// 返回一个对象
|
||
function getC(): C { return new C; }
|
||
```
|
||
|
||
### 可空返回类型
|
||
|
||
```php
|
||
// 在 PHP 7.1 中可用
|
||
function nullOrString(int $v) : ?string
|
||
{
|
||
return $v % 2 ? "odd" : null;
|
||
}
|
||
echo nullOrString(3); # => odd
|
||
var_dump(nullOrString(4)); # => NULL
|
||
```
|
||
|
||
查看: [Nullable types](https://www.php.net/manual/en/migration71.new-features.php)
|
||
|
||
### 无效函数
|
||
|
||
```php
|
||
// 在 PHP 7.1 中可用
|
||
function voidFunction(): void
|
||
{
|
||
echo 'Hello';
|
||
return;
|
||
}
|
||
voidFunction(); # => Hello
|
||
```
|
||
|
||
### 变量函数
|
||
|
||
```php
|
||
function bar($arg = '')
|
||
{
|
||
echo "In bar(); arg: '$arg'.\n";
|
||
}
|
||
$func = 'bar';
|
||
$func('test'); # => In bar(); arg: test
|
||
```
|
||
|
||
### 匿名函数
|
||
|
||
```php
|
||
$greet = function($name)
|
||
{
|
||
printf("Hello %s\r\n", $name);
|
||
};
|
||
$greet('World'); # => Hello World
|
||
$greet('PHP'); # => Hello PHP
|
||
```
|
||
|
||
### 递归函数
|
||
|
||
```php
|
||
function recursion($x)
|
||
{
|
||
if ($x < 5) {
|
||
echo "$x";
|
||
recursion($x + 1);
|
||
}
|
||
}
|
||
recursion(1); # => 1234
|
||
```
|
||
|
||
### 默认参数
|
||
|
||
```php
|
||
function coffee($type = "cappuccino")
|
||
{
|
||
return "Making a cup of $type.\n";
|
||
}
|
||
# => 制作一杯卡布奇诺
|
||
echo coffee();
|
||
# => 制作一杯
|
||
echo coffee(null);
|
||
# => 制作一杯浓缩咖啡
|
||
echo coffee("espresso");
|
||
```
|
||
|
||
### 箭头函数
|
||
|
||
```php
|
||
$y = 1;
|
||
|
||
$fn1 = fn($x) => $x + $y;
|
||
// 相当于按值使用 $y：
|
||
$fn2 = function ($x) use ($y) {
|
||
return $x + $y;
|
||
};
|
||
echo $fn1(5); # => 6
|
||
echo $fn2(5); # => 6
|
||
```
|
||
|
||
PHP 类
|
||
------
|
||
|
||
### 构造函数 Constructor
|
||
|
||
```php
|
||
class Student {
|
||
public function __construct($name) {
|
||
$this->name = $name;
|
||
}
|
||
public function print() {
|
||
echo "Name: " . $this->name;
|
||
}
|
||
}
|
||
$alex = new Student("Alex");
|
||
$alex->print(); # => Name: Alex
|
||
```
|
||
|
||
### 继承 Inheritance
|
||
|
||
```php
|
||
class ExtendClass extends SimpleClass
|
||
{
|
||
// 重新定义父方法
|
||
function displayVar()
|
||
{
|
||
echo "Extending class\n";
|
||
parent::displayVar();
|
||
}
|
||
}
|
||
$extended = new ExtendClass();
|
||
$extended->displayVar();
|
||
```
|
||
|
||
### 类变量 Classes variables
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
|
||
```php
|
||
class MyClass
|
||
{
|
||
const MY_CONST = 'value';
|
||
static $staticVar = 'static';
|
||
// 可见度
|
||
public static $var1 = 'pubs';
|
||
// 仅限类
|
||
private static $var2 = 'pris';
|
||
// 类和子类
|
||
protected static $var3 = 'pros';
|
||
// 类和子类
|
||
protected $var6 = 'pro';
|
||
// 仅限类
|
||
private $var7 = 'pri';
|
||
}
|
||
```
|
||
|
||
静态访问
|
||
|
||
```php
|
||
echo MyClass::MY_CONST; # => value
|
||
echo MyClass::$staticVar; # => static
|
||
```
|
||
|
||
### 魔术方法
|
||
|
||
```php
|
||
class MyClass
|
||
{
|
||
// 对象被视为字符串
|
||
public function __toString()
|
||
{
|
||
return $property;
|
||
}
|
||
// 与 __construct() 相反
|
||
public function __destruct()
|
||
{
|
||
print "Destroying";
|
||
}
|
||
}
|
||
```
|
||
|
||
### 接口
|
||
|
||
```php
|
||
interface Foo
|
||
{
|
||
public function doSomething();
|
||
}
|
||
interface Bar
|
||
{
|
||
public function doSomethingElse();
|
||
}
|
||
class Cls implements Foo, Bar
|
||
{
|
||
public function doSomething() {}
|
||
public function doSomethingElse() {}
|
||
}
|
||
```
|
||
|
||
各种各样的
|
||
------
|
||
|
||
### 基本错误处理
|
||
|
||
```php
|
||
try {
|
||
// 做一点事
|
||
} catch (Exception $e) {
|
||
// 处理异常
|
||
} finally {
|
||
echo "Always print!";
|
||
}
|
||
```
|
||
|
||
### PHP 8.0 中的异常
|
||
|
||
<!--rehype:wrap-class=col-span-2-->
|
||
```php {.wrap}
|
||
$nullableValue = null;
|
||
try {
|
||
$value = $nullableValue ?? throw new InvalidArgumentException();
|
||
} catch (InvalidArgumentException) { // 变量是可选的
|
||
// 处理我的异常
|
||
echo "print me!";
|
||
}
|
||
```
|
||
|
||
### 自定义异常
|
||
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
```php
|
||
class MyException extends Exception {
|
||
// 做一点事
|
||
}
|
||
```
|
||
|
||
用法
|
||
|
||
```php
|
||
try {
|
||
$condition = true;
|
||
if ($condition) {
|
||
throw new MyException('bala');
|
||
}
|
||
} catch (MyException $e) {
|
||
// 处理我的异常
|
||
}
|
||
```
|
||
|
||
### Nullsafe 运算符
|
||
<!--rehype:wrap-class=row-span-2-->
|
||
|
||
```php
|
||
// 从 PHP 8.0.0 开始，这一行：
|
||
$result = $repo?->getUser(5)?->name;
|
||
// 相当于下面的代码：
|
||
if (is_null($repo)) {
|
||
$result = null;
|
||
} else {
|
||
$user = $repository->getUser(5);
|
||
if (is_null($user)) {
|
||
$result = null;
|
||
} else {
|
||
$result = $user->name;
|
||
}
|
||
}
|
||
```
|
||
|
||
另见: [Nullsafe 运算符](https://wiki.php.net/rfc/nullsafe_operator)
|
||
|
||
### 常用表达
|
||
|
||
```php
|
||
$str = "Visit jaywcjlove.github.io";
|
||
echo preg_match("/qu/i", $str); # => 1
|
||
```
|
||
|
||
查看: [PHP中的正则表达式](./regex.md#php中的正则表达式)
|
||
|
||
### fopen() 模式
|
||
|
||
:- | -
|
||
:- | -
|
||
`r` | 读
|
||
`r+` | 读写，前置
|
||
`w` | 写入，截断
|
||
`w+` | 读写，截断
|
||
`a` | 写，追加
|
||
`a+` | 读写，追加
|
||
|
||
### 运行时定义的常量
|
||
|
||
```php
|
||
define("CURRENT_DATE", date('Y-m-d'));
|
||
// 一种可能的表示
|
||
echo CURRENT_DATE; # => 2021-01-05
|
||
# => CURRENT_DATE is: 2021-01-05
|
||
echo 'CURRENT_DATE is: ' . CURRENT_DATE;
|
||
```
|
||
|
||
另见
|
||
----
|
||
|
||
- [PHP 官方中文文档](https://www.php.net/manual/zh/index.php) _(php.net)_
|
||
- [Learn X in Y minutes](https://learnxinyminutes.com/docs/zh-cn/php-cn/) _(learnxinyminutes.com)_
|