php -i查看 php.ini 配置文件
不输出错误原因：可能是 php.ini 导致的 (log 的配置问题, grep 配置排查下）

类型

  • string
  • int
  • float
  • bool

类型断言

is_string($x)
is_bool($x)

类型转换

  1. $str = "123";
  2. $int = 2020;
  3. $float = 99.0;
  4. $bool = false;
  6. var_dump((int) $str);
  7. var_dump((bool) $str);
  8. var_dump((string) $str);
  9. var_dump((bool) $str);
  10. var_dump((int) $float);
  11. var_dump((string) $float);
  12. var_dump((string) $bool);
  13. var_dump((int) $bool);

数组

var_dump($arr)查看详细的数据，包括类型
print_r($arr)查看数据，隐去类型

追加数据：

  1. $arr = [];
  2. $arr[] = "Java";
  3. $arr[] = "Python";
  4. $arr[] = "Golang";
  5. print_r($arr);
  7. // 遍历数据
  8. foreach ($arr as $item)
  9. {
  10.   printf("%s\n", $item);
  11. }

Map 

  1. $strangeMap = [
  2.   "dog" => "狗",
  3.   "cat" => "猫",
  4. ];
  5. $strangeMap["fish"] = "鱼";
  6. print_r($strangeMap);
  8. // 遍历
  9. foreach ($strangeMap as $k => $v)
  10. {
  11.   printf("%s => %s\n", $k, $v);
  12. }

运算符

php 是弱类型 ===``!==
|| &&

函数

  1. // 申明变量与返回值的类型
  2. $add = function (int $x, int $y): int
  3. {
  4.   return $x + $y;
  5. };
  6. printf("=> %d\n", $add(2, 3));
  9. // 引用传递
  10. function add(int &$a, int $b) {
  11.   $a += $b;
  12. }

异常处理

  1.   try {
  2.     printf("exception demo!!!");
  3.   } catch (Throwable $e) {
  4.     Logger::info("Exception: %s\n", $e->getMessage());
  5.   }

自定义异常：

面向对象

  • 对于通过 public 声明的属性和方法，在类以外和继承类中均可见；
  • 对于通过 protected 声明的属性和方法，仅在继承类（支持多个层级）中可见，在类以外不可见；

  • 对于通过 private 声明的属性和方法，仅在当前类内部可见，在继承类和类之外不可 ```php abstract class Car { var $brand; var $wheelNum; var $maxSpeed;

    /**

    • Car constructor.
    • @param $brand
    • @param $wheelNum

    • @param $maxSpeed */ public function __construct(string $brand, int $wheelNum, int $maxSpeed) { $this->brand = $brand; $this->wheelNum = $wheelNum; $this->maxSpeed = $maxSpeed; }

      public function run(): void { printf(“%s is running\n”, $this->brand); } }

class Tesla extends Car {

  1. /**
  2.  * Tesla constructor.
  3.  * @param $brand
  4.  */
  5. public function __construct(string $brand)
  6. {
  7.     parent::__construct($brand, 4, 120);
  8. }

}

  1. 不要使用继承，使用面向接口编程
  2. ```php
  3. interface Car
  4. {
  5.     public function run(): void;
  6. }
  8. class CarFramework
  9. {
  10.     var $wheelNum;
  11.     var $maxSpeed;
  13.     /**
  14.      * CarFramework constructor.
  15.      * @param $wheelNum
  16.      * @param $maxSpeed
  17.      */
  18.     public function __construct($wheelNum, $maxSpeed)
  19.     {
  20.         $this->wheelNum = $wheelNum;
  21.         $this->maxSpeed = $maxSpeed;
  22.     }
  23. }
  25. class Tesla implements Car
  26. {
  27.     var $carFramework;
  28.     var $brand;
  30.     /**
  31.      * Tesla constructor.
  32.      * @param $carFramework
  33.      * @param $brand
  34.      */
  35.     public function __construct($carFramework, $brand)
  36.     {
  37.         $this->carFramework = $carFramework;
  38.         $this->brand = $brand;
  39.     }
  41.     public function run(): void
  42.     {
  43.         printf("%s is running.", $this->brand);
  44.         printf(
  45.             "Info => wheel: %d, max speed: %d\n",
  46.             $this->carFramework->wheelNum,
  47.             $this->carFramework->maxSpeed
  48.         );
  49.     }
  50. }
  52. // using
  53. $tesla = new Tesla(new CarFramework(4, 120), "Tesla");
  54. $tesla->run();