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PHP 速记表 ​

基础语法

Hello World

<?php
echo "Hello, World!";
?>

输入输出

<?php
// 输出
echo "Hello, World!";
print "Hello, World!";
printf("Name: %s, Age: %d\n", "Alice", 25);
// 命令行输入
$name = readline("Enter your name: ");
echo "Hello, " . $name . "!\n";
// Web 表单输入
$name = $_POST['name'] ?? '';
$age = $_GET['age'] ?? 0;
?>

注释

<?php
// 单行注释
# 单行注释（shell 风格）
/* 多行注释
   可以换行 */
/**
 * PHPDoc 文档注释
 * @param string $name
 * @return string
 */

变量与常量

变量声明

<?php
$name = "Alice";
$age = 25;
$pi = 3.14;
$isValid = true;
// 变量变量
$var = "name";
$$var = "Bob";  // $name = "Bob"

常量

define('MAX', 100);
const API_KEY = "secret";  // PHP 5.3+
// 魔术常量
__FILE__      // 文件路径
__LINE__      // 行号
__DIR__       // 目录
__FUNCTION__  // 函数名
__CLASS__     // 类名
__METHOD__    // 方法名

作用域

$globalVar = "global";  // 全局作用域
function example() {
    global $globalVar;  // 使用全局变量
    $localVar = "local";  // 局部作用域
    static $staticVar = 0;  // 静态变量
    $staticVar++;
}

数据类型

标量类型

// 整数
$int = 42;
$hex = 0x1A;
$octal = 0123;
$binary = 0b1010;
// 浮点数
$float = 3.14;
$scientific = 1.2e3;
// 字符串
$str = "hello";
$str = 'world';
// 布尔
$bool = true;
$bool = false

复合类型

// 数组
$arr = [1, 2, 3];
$arr = array(1, 2, 3);
// 对象
$obj = new stdClass();
$obj->name = "Alice";
// 资源
$file = fopen("file.txt", "r");
// NULL
$null = null;

类型声明

PHP 7+

function add(int $a, int $b): int {
    return $a + $b;
}
function greet(string $name): void {
    echo "Hello, $name";
}
// PHP 7.4+ 属性类型
class User {
    public string $name;
    public int $age;
}

类型转换

(int)$value
(float)$value
(string)$value
(bool)$value
(array)$value
(object)$value
intval($value)
floatval($value)
strval($value)

运算符

算术运算符

+  -  *  /  %  **
++  --

比较运算符

==  !=  <>        // 相等
===  !==          // 全等
>  <  >=  <=
<=>               // 太空船运算符 (PHP 7+)

逻辑运算符

&&  and
||  or
!   not
xor

字符串运算符

.          // 拼接
.=         // 拼接赋值

赋值运算符

=  +=  -=  *=  /=  %=  **=
.=  &=  |=  ^=  <<=  >>=

Null 运算符

PHP 7+

// Null 合并
$name = $_GET['name'] ?? 'default';
// Null 安全 (PHP 8+)
$name = $user?->profile?->name;

字符串

字符串创建

$str = "hello";
$str = 'world';
// Heredoc
$text = <<<EOT
Multi-line
string
EOT;
// Nowdoc (PHP 5.3+)
$text = <<<'EOT'
No variable
interpolation
EOT;

字符串插值

$name = "Alice";
$age = 25;
echo "Name: $name, Age: $age";
echo "Name: {$name}, Age: {$age}";
echo 'Name: ' . $name . ', Age: ' . $age;

字符串函数

strlen($str)
strtoupper($str)
strtolower($str)
ucfirst($str)
ucwords($str)
trim($str)
ltrim($str)
rtrim($str)
substr($str, 0, 5)
strpos($str, 'sub')
str_replace('old', 'new', $str)
str_contains($str, 'sub')  // PHP 8+
str_starts_with($str, 'pre')  // PHP 8+
str_ends_with($str, 'fix')  // PHP 8+

字符串分割与拼接

$parts = explode(' ', $str);
$joined = implode('-', $parts);
$result = join(', ', $arr);

正则表达式

preg_match('/pattern/', $str, $matches);
preg_match_all('/pattern/', $str, $matches);
preg_replace('/old/', 'new', $str);
preg_split('/\s+/', $str);

数组

数组创建

$arr = [1, 2, 3, 4, 5];
$arr = array(1, 2, 3);
// 关联数组
$person = [
    'name' => 'Alice',
    'age' => 25
];

数组操作

array_push($arr, 6);
$arr[] = 7;
array_pop($arr);
array_shift($arr);
array_unshift($arr, 0);
count($arr);
in_array(5, $arr);
array_key_exists('key', $arr);

数组函数

array_map(fn($x) => $x * 2, $arr);
array_filter($arr, fn($x) => $x &gt; 5);
array_reduce($arr, fn($acc, $x) => $acc + $x, 0);
array_slice($arr, 1, 3);
array_merge($arr1, $arr2);
array_unique($arr);
sort($arr);
rsort($arr);
asort($arr);  // 保持键关联
ksort($arr);  // 按键排序

遍历数组

foreach ($arr as $value) {
    echo $value;
}
foreach ($arr as $key => $value) {
    echo "$key: $value";
}
// 引用修改
foreach ($arr as &$value) {
    $value *= 2;
}

数组解构

PHP 7.1+

[$a, $b] = [1, 2];
['name' => $name, 'age' => $age] = $person;

控制流

if / else

if ($condition) {
    // 执行
} elseif ($other) {
    // 执行
} else {
    // 执行
}
// 三元运算符
$result = $condition ? 'yes' : 'no';

switch

switch ($value) {
    case 1:
        echo "one";
        break;
    case 2:
    case 3:
        echo "two or three";
        break;
    default:
        echo "other";
}

match

PHP 8+

$result = match($status) {
    'success' => 'Operation successful',
    'error' => 'Operation failed',
    default => 'Unknown status'
};

for 循环

for ($i = 0; $i < 10; $i++) {
    echo $i;
}
foreach ($arr as $value) {
    echo $value;
}
foreach ($arr as $key => $value) {
    echo "$key: $value";
}

while 循环

while ($condition) {
    // 执行
}
do {
    // 至少执行一次
} while ($condition);

跳转语句

break;       // 退出循环
continue;    // 跳过本次
return $value; // 返回值
goto label;  // 跳转

函数

函数定义

function add($a, $b) {
    return $a + $b;
}
// 默认参数
function greet($name = "Guest") {
    return "Hello, $name";
}
// 类型声明 (PHP 7+)
function sum(int $a, int $b): int {
    return $a + $b;
}

箭头函数

PHP 7.4+

$square = fn($x) => $x * $x;
$add = fn($a, $b) => $a + $b;
// 自动捕获外部变量
$factor = 2;
$multiply = fn($x) => $x * $factor;

匿名函数

$greet = function($name) {
    return "Hello, $name";
};
// use 捕获外部变量
$multiplier = 2;
$multiply = function($x) use ($multiplier) {
    return $x * $multiplier;
};

可变参数

function sum(...$nums) {
    return array_sum($nums);
}
$result = sum(1, 2, 3, 4, 5);
// 解包参数
$arr = [1, 2, 3];
sum(...$arr);

命名参数

PHP 8+

function createUser($name, $email, $age) {
    // ...
}
createUser(
    name: 'Alice',
    age: 25,
    email: 'alice@example.com'
);

面向对象

类定义

class Person {
    private $name;
    protected $age;
    public $email;
    public function __construct($name, $age) {
        $this->name = $name;
        $this->age = $age;
    }
    public function greet() {
        return "Hello, I'm {$this->name}";
    }
    public static function species() {
        return "Human";
    }
}
$person = new Person("Alice", 25);

构造器属性提升

PHP 8+

class Person {
    public function __construct(
        public string $name,
        public int $age,
        private string $email = ""
    ) {}
}
$person = new Person("Alice", 25);
echo $person->name;

继承

class Student extends Person {
    private $major;
    public function __construct($name, $age, $major) {
        parent::__construct($name, $age);
        $this->major = $major;
    }
    public function study() {
        echo "Studying $this->major";
    }
}

接口与抽象类

interface Drawable {
    public function draw();
}
abstract class Shape {
    abstract public function area();
    public function describe() {
        echo "This is a shape";
    }
}
class Circle extends Shape implements Drawable {
    public function area() {
        return 3.14 * $this->radius ** 2;
    }
    public function draw() {
        echo "Drawing circle";
    }
}

Trait

trait Logger {
    public function log($message) {
        echo "[LOG] $message";
    }
}
class User {
    use Logger;
}
$user = new User();
$user->log("User created");

魔术方法

class MyClass {
    public function __construct() {}
    public function __destruct() {}
    public function __toString() {}
    public function __get($name) {}
    public function __set($name, $value) {}
    public function __call($name, $args) {}
    public function __invoke() {}
}

Enum

PHP 8.1+

enum Status {
    case Pending;
    case Approved;
    case Rejected;
}
$status = Status::Pending;
// Backed Enum
enum HttpStatus: int {
    case OK = 200;
    case NotFound = 404;
    case ServerError = 500;
}

错误处理

try/catch

try {
    throw new Exception("Something went wrong");
} catch (Exception $e) {
    echo "Error: " . $e->getMessage();
} finally {
    echo "Always executed";
}

多重捕获

PHP 7.1+

try {
    // 可能抛出异常
} catch (RuntimeException | InvalidArgumentException $e) {
    echo "Error: " . $e->getMessage();
}

自定义异常

class ValidationException extends Exception {
    public function __construct($message) {
        parent::__construct($message);
    }
}
throw new ValidationException("Invalid input");

文件操作

读取文件

// 读取全部
$content = file_get_contents('file.txt');
// 读取行数组
$lines = file('file.txt');
// 逐行读取
$handle = fopen('file.txt', 'r');
while (($line = fgets($handle)) !== false) {
    echo $line;
}
fclose($handle);

写入文件

// 写入全部
file_put_contents('file.txt', 'content');
// 追加
file_put_contents('file.txt', 'append', FILE_APPEND);
// 逐行写入
$handle = fopen('file.txt', 'w');
fwrite($handle, "Hello\n");
fclose($handle);

文件系统

file_exists($path);
is_file($path);
is_dir($path);
filesize($path);
filemtime($path);
unlink($file);  // 删除文件
mkdir($dir);
rmdir($dir);
rename($old, $new);

JSON 操作

// 序列化
$json = json_encode($array);
$json = json_encode($data, JSON_PRETTY_PRINT);
// 反序列化
$array = json_decode($json, true);
$obj = json_decode($json);

超全局变量

HTTP 请求

$_GET['param'];
$_POST['field'];
$_REQUEST['data'];
$_SERVER['REQUEST_METHOD'];
$_SERVER['HTTP_HOST'];
$_SERVER['REQUEST_URI'];
$_FILES['upload'];
$_COOKIE['session'];
$_SESSION['user'];
$_ENV['APP_KEY'];

处理表单

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $name = $_POST['name'] ?? 'default';
    $email = filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL);
    if ($email === false) {
        echo "Invalid email";
    }
}

数据库

PDO

$pdo = new PDO('mysql:host=localhost;dbname=test', 'user', 'pass');
// 查询
$stmt = $pdo->query('SELECT * FROM users');
$users = $stmt->fetchAll(PDO::FETCH_ASSOC);
// 预处理语句
$stmt = $pdo->prepare('SELECT * FROM users WHERE id = ?');
$stmt->execute([$id]);
$user = $stmt->fetch();
// 插入
$stmt = $pdo->prepare('INSERT INTO users (name, email) VALUES (?, ?)');
$stmt->execute([$name, $email]);

MySQLi

$mysqli = new mysqli('localhost', 'user', 'pass', 'test');
// 查询
$result = $mysqli->query('SELECT * FROM users');
while ($row = $result->fetch_assoc()) {
    echo $row['name'];
}
// 预处理
$stmt = $mysqli->prepare('SELECT * FROM users WHERE id = ?');
$stmt->bind_param('i', $id);
$stmt->execute();
$result = $stmt->get_result();

常用函数

日期时间

date('Y-m-d H:i:s');
time();
strtotime('2024-01-01');
strtotime('+1 day');
$dt = new DateTime();
$formatted = $dt->format('Y-m-d');
$dt->modify('+1 day');

数学函数

abs($x);
ceil($x);
floor($x);
round($x);
max($a, $b, $c);
min($a, $b, $c);
pow($base, $exp);
sqrt($x);
rand($min, $max);

类型检查

is_int($var);
is_string($var);
is_array($var);
is_object($var);
is_null($var);
is_numeric($var);
is_callable($var);
gettype($var);
get_class($obj);

输出控制

echo "Hello";
print "World";
var_dump($var);
print_r($array);
var_export($data);
header('Content-Type: application/json');
header('Location: /page.php');
http_response_code(404);

最佳实践

代码风格 (PSR-12)

// 使用类型声明
function add(int $a, int $b): int {
    return $a + $b;
}
// 使用 null 合并
$name = $_GET['name'] ?? 'default';
// 使用严格类型 (PHP 7+)
declare(strict_types=1);

安全性

// 防止 SQL 注入
$stmt = $pdo->prepare('SELECT * FROM users WHERE id = ?');
$stmt->execute([$id]);
// 防止 XSS
echo htmlspecialchars($userInput, ENT_QUOTES, 'UTF-8');
// 密码哈希
$hash = password_hash($password, PASSWORD_DEFAULT);
password_verify($password, $hash);
// CSRF 令牌
$token = bin2hex(random_bytes(32));

常见陷阱

// == vs ===
0 == '0'   // true
0 === '0'  // false
// 数组键
$arr[0] !== $arr['0']  // false (相同)
// 字符串连接性能
// 用 . 而非 += 拼接大量字符串
$parts = [];
$parts[] = $str1;
$parts[] = $str2;
$result = implode('', $parts);

工具链

Composer

# 安装依赖
composer install
composer require package
# 自动加载
composer dump-autoload
# 更新
composer update

测试框架

# PHPUnit
./vendor/bin/phpunit
# Pest
./vendor/bin/pest

代码质量

# PHP-CS-Fixer (格式化)
php-cs-fixer fix
# PHPStan (静态分析)
phpstan analyse
# Psalm (静态分析)
psalm

框架

# Laravel
composer create-project laravel/laravel myapp
php artisan serve
# Symfony
composer create-project symfony/skeleton myapp
symfony serve