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PHP 速查表
这份 PHP 快速查找最常用代码的正确语法提供了参考
入门
hello.php
<?php // 以 PHP 开放标签开头 echo "Hello World\n"; print("Hello jaywcjlove.github.io"); ?>
PHP 运行命令
$ php hello.php
变量 Variables
$boolean1 = true; $boolean2 = True; $int = 12; $float = 3.1415926; unset($float); // 删除变量 $str1 = "How are you?"; $str2 = 'Fine, thanks';
字符串 Strings
$url = "jaywcjlove.github.io"; echo "I'm learning PHP at $url"; // 连接字符串 echo "I'm learning PHP at " . $url; $hello = "Hello, "; $hello .= "World!"; echo $hello; # => Hello, World!
数组 Arrays
$num = [1, 3, 5, 7, 9]; $num[5] = 11; unset($num[2]); // 删除变量 print_r($num); # => 1 3 7 9 11 echo count($num); # => 5
运算符 Operators
$x = 1; $y = 2; $sum = $x + $y; echo $sum; # => 3
Include
vars.php
<?php // 以 PHP 开放标签开头。 $fruit = 'apple'; echo "I was imported"; return 'Anything you like.'; ?>
test.php
<?php include 'vars.php'; echo $fruit . "\n"; # => apple /* 与 include 相同， 如果不能包含则导致错误*/ require 'vars.php'; // 也有效 include('vars.php'); require('vars.php'); // 通过 HTTP 包含 include 'http://x.com/file.php'; // 包含和返回语句 $result = include 'vars.php'; echo $result; # => Anything you like. ?>
功能 Functions
function add($num1, $num2 = 1) { return $num1 + $num2; } echo add(10); # => 11 echo add(10, 5); # => 15
注释 Comments
# 这是一个单行 shell 样式的注释 // 这是一行 c++ 风格的注释 /* 这是一个多行注释 另一行注释 */
常数 Constants
const MY_CONST = "hello"; echo MY_CONST; # => hello # => MY_CONST is: hello echo 'MY_CONST is: ' . MY_CONST;
类 Classes
class Student { public function __construct($name) { $this->name = $name; } } $alex = new Student("Alex");
PHP 类型
布尔值 Boolean
$boolean1 = true; $boolean2 = TRUE; $boolean3 = false; $boolean4 = FALSE; $boolean5 = (boolean) 1; # => true $boolean6 = (boolean) 0; # => false
布尔值不区分大小写
整数 Integer
$int1 = 28; # => 28 $int2 = -32; # => -32 $int3 = 012; # => 10 (octal) $int4 = 0x0F; # => 15 (hex) $int5 = 0b101; # => 5 (binary) # => 2000100000 (decimal, PHP 7.4.0) $int6 = 2_000_100_000;
字符串 Strings
echo 'this is a simple string';
数组 Arrays
$arr = array("hello", "world", "!");
浮点数 Float (Double)
$float1 = 1.234; $float2 = 1.2e7; $float3 = 7E-10; $float4 = 1_234.567; // as of PHP 7.4.0 var_dump($float4); // float(1234.567) $float5 = 1 + "10.5"; # => 11.5 $float6 = 1 + "-1.3e3"; # => -1299
Null
$a = null; $b = 'Hello php!'; echo $a ?? 'a is unset'; # => a is unset echo $b ?? 'b is unset'; # => Hello php $a = array(); $a == null # => true $a === null # => false is_null($a) # => false
可迭代对象 Iterables
function bar(): iterable { return [1, 2, 3]; } function gen(): iterable { yield 1; yield 2; yield 3; } foreach (bar() as $value) { echo $value; # => 123 }
PHP 字符串
字符串 String
# => '$String' $sgl_quotes = '$String'; # => 'This is a $String.' $dbl_quotes = "This is a $sgl_quotes."; # => a tab character. $escaped = "a \t tab character."; # => a slash and a t: \t $unescaped = 'a slash and a t: \t';
多行 Multi-line
$str = "foo"; // 未插值的多行 $nowdoc = <<<'END' Multi line string $str END; // 将执行字符串插值 $heredoc = <<<END Multi line $str END;
操作 Manipulation
$s = "Hello Phper"; echo strlen($s); # => 11 echo substr($s, 0, 3); # => Hel echo substr($s, 1); # => ello Phper echo substr($s, -4, 3);# => hpe echo strtoupper($s); # => HELLO PHPER echo strtolower($s); # => hello phper echo strpos($s, "l"); # => 2 var_dump(strpos($s, "L")); # => false
PHP 数组
定义
$a1 = ["hello", "world", "!"] $a2 = array("hello", "world", "!"); $a3 = explode(",", "apple,pear,peach");
混合 int 和 string 键
$array = array( "foo" => "bar", "bar" => "foo", 100 => -100, -100 => 100, ); var_dump($array);
短数组语法
$array = [ "foo" => "bar", "bar" => "foo", ];
多阵列
$multiArray = [ [1, 2, 3], [4, 5, 6], [7, 8, 9], ]; print_r($multiArray[0][0]) # => 1 print_r($multiArray[0][1]) # => 2 print_r($multiArray[0][2]) # => 3
多类型
$array = array( "foo" => "bar", 42 => 24, "multi" => array( "dim" => array( "a" => "foo" ) ) ); # => string(3) "bar" var_dump($array["foo"]); # => int(24) var_dump($array[42]); # => string(3) "foo" var_dump($array["multi"]["dim"]["a"]);
操作
$arr = array(5 => 1, 12 => 2); $arr[] = 56; // 附加 $arr["x"] = 42; // 用键添加 sort($arr); // 排序 unset($arr[5]); // 消除 unset($arr); // 移除所有
索引迭代
$array = array('a', 'b', 'c'); $count = count($array); for ($i = 0; $i < $count; $i++) { echo "i:{$i}, v:{$array[$i]}\n"; }
价值迭代
$colors = array('red', 'blue', 'green'); foreach ($colors as $color) { echo "Do you like $color?\n"; }
关键迭代
$arr = ["foo" => "bar", "bar" => "foo"]; foreach ( $arr as $key => $value ) { echo "key: " . $key . "\n"; echo "val: {$arr[$key]}\n"; }
串联阵列
$a = [1, 2]; $b = [3, 4]; // PHP 7.4 以后 # => [1, 2, 3, 4] $result = [...$a, ...$b];
Into 函数
$array = [1, 2]; function foo(int $a, int $b) { echo $a; # => 1 echo $b; # => 2 } foo(...$array);
Splat运算符
function foo($first, ...$other) { var_dump($first); # => a var_dump($other); # => ['b', 'c'] } foo('a', 'b', 'c' /*, ...*/ ); // 或 function foo($first, string ...$other){}
PHP 运算符
算术
| :- | – |
| + | 添加 |
| – | 减法 |
| * | 乘法 |
| / | 分配 |
| % | 取模 |
| ** | 求幂 |
分配
| :- | – |
| a += b | 如同 a = a + b |
| a -= b | 如同 a = a – b |
| a *= b | 如同 a = a * b |
| a /= b | 如同 a = a / b |
| a %= b | 如同 a = a % b |
比较
| :- | – |
| == | 平等的 |
| === | 完全相同的 |
| != | 不相等 |
| <> | 不相等 |
| !== | 不相同 |
| < | 少于 |
| > | 比…更棒 |
| <= | 小于或等于 |
| >= | 大于或等于 |
| <=> | 小于/等于/大于 |
逻辑的
| :- | – |
| and | 和 |
| or | 或者 |
| xor | 独家或 |
| ! | 不是 |
| && | 和 |
| || | 或者 |
算术
// 算术 $sum = 1 + 1; // 2 $difference = 2 - 1; // 1 $product = 2 * 2; // 4 $quotient = 2 / 1; // 2 // 速记算术 $num = 0; $num += 1; // 将 $num 增加 1 echo $num++; // 打印 1（评估后的增量） echo ++$num; // 打印 3（评估前的增量） $num /= $float; // 将商除并分配给 $num
按位
| :- | – | 或（包括或） |
| & | 和 | |
| ` | ` | |
| ^ | 异或（异或） | |
| ~ | 不是 | |
| << | 左移 | |
| >> | 右移 |
PHP 条件
If elseif else
$a = 10; $b = 20; if ($a > $b) { echo "a is bigger than b"; } elseif ($a == $b) { echo "a is equal to b"; } else { echo "a is smaller than b"; }
Switch
$x = 0; switch ($x) { case '0': print "it's zero"; break; case 'two': case 'three': // do something break; default: // do something }
三元运算符
# => Does print (false ? 'Not' : 'Does'); $x = false; # => Does print($x ?: 'Does'); $a = null; $b = 'Does print'; # => a is unsert echo $a ?? 'a is unset'; # => print echo $b ?? 'b is unset';
匹配
$statusCode = 500; $message = match($statusCode) { 200, 300 => null, 400 => '未找到', 500 => '服务器错误', default => '已知状态码', }; echo $message; # => 服务器错误
匹配表达式
$age = 23; $result = match (true) { $age >= 65 => 'senior', $age >= 25 => 'adult', $age >= 18 => 'young adult', default => 'kid', }; echo $result; # => young adult
PHP 循环
while 循环
$i = 1; # => 12345 while ($i <= 5) { echo $i++; }
do while 循环
$i = 1; # => 12345 do { echo $i++; } while ($i <= 5);
for i 循环
# => 12345 for ($i = 1; $i <= 5; $i++) { echo $i; }
break 跳出循环
# => 123 for ($i = 1; $i <= 5; $i++) { if ($i === 4) { break; } echo $i; }
continue 继续
# => 1235 for ($i = 1; $i <= 5; $i++) { if ($i === 4) { continue; } echo $i; }
foreach 循环
$a = ['foo' => 1, 'bar' => 2]; # => 12 foreach ($a as $k) { echo $k; }
PHP 函数
返回值
function square($x) { return $x * $x; } echo square(4); # => 16
返回类型
// 基本返回类型声明 function sum($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
// 在 PHP 7.1 中可用 function nullOrString(int $v) : ?string { return $v % 2 ? "odd" : null; } echo nullOrString(3); # => odd var_dump(nullOrString(4)); # => NULL
无效函数
// 在 PHP 7.1 中可用 function voidFunction(): void { echo 'Hello'; return; } voidFunction(); # => Hello
变量函数
function bar($arg = '') { echo "In bar(); arg: '$arg'.\n"; } $func = 'bar'; $func('test'); # => In bar(); arg: test
匿名函数
$greet = function($name) { printf("Hello %s\r\n", $name); }; $greet('World'); # => Hello World $greet('PHP'); # => Hello PHP
递归函数
function recursion($x) { if ($x < 5) { echo "$x"; recursion($x + 1); } } recursion(1); # => 1234
默认参数
function coffee($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
$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 $fn2(5); # => 6
PHP 类
构造函数 Constructor
class Student { public function __construct($name) { $this->name = $name; } public function print() { echo "Name: " . $this->name; } } $alex = new Student("Alex"); $alex->print(); # => Name: Alex
继承 Inheritance
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
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 $var7 = 'pri'; }
静态访问
echo MyClass::MY_CONST; # => value echo MyClass::$staticVar; # => static
魔术方法
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
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
try { // 做一点事 } catch (Exception $e) { // 处理异常 } finally { echo "Always print!"; }
PHP 8.0 中的异常
$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
class MyException extends Exception { // 做一点事 }
用法
try { $condition = true; if ($condition) { throw new MyException('bala'); } } catch (MyException $e) { // 处理我的异常 }
Nullsafe 运算符
// 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; } }
常用表达
$str = "Visit jaywcjlove.github.io"; echo preg_match("/qu/i", $str); # => 1
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
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;