Usage analysis of PHP array access interface ArrayAccess

This article mainly introduces the usage of PHP array access interface ArrayAccess, and analyzes the concept, function, implementation and usage of array access interface ArrayAccess in the form of examples. Friends in need can refer to this article

The example describes the usage of PHP array access interface ArrayAccess. Share it with everyone for your reference, the details are as follows:

PHP The ArrayAccess interface is also called the array access interface. The function of this interface is to provide the ability to access objects like accessing arrays.

The interface summary is as follows:

ArrayAccess {
  // 获取一个偏移位置的值
  abstract public mixed offsetGet ( mixed $offset )
  // 设置一个偏移位置的值
  abstract public void offsetSet ( mixed $offset , mixed $value )
  // 检查一个偏移位置是否存在
  abstract public boolean offsetExists ( mixed $offset )
  // 复位一个偏移位置的值
  abstract public void offsetUnset ( mixed $offset )
}

Example description:

<?php
/**
* ArrayAndObjectAccess
* 该类允许以数组或对象的方式进行访问
*
* @author 疯狂老司机
*/
class ArrayAndObjectAccess implements ArrayAccess {
  /**
   * 定义一个数组用于保存数据
   *
   * @access private
   * @var array
   */
  private $data = [];
  /**
   * 以对象方式访问数组中的数据
   *
   * @access public
   * @param string 数组元素键名
   */
  public function __get($key) {
    return $this->data[$key];
  }
  /**
   * 以对象方式添加一个数组元素
   *
   * @access public
   * @param string 数组元素键名
   * @param mixed 数组元素值
   * @return mixed
   */
  public function __set($key,$value) {
    $this->data[$key] = $value;
  }
  /**
   * 以对象方式判断数组元素是否设置
   *
   * @access public
   * @param 数组元素键名
   * @return boolean
   */
  public function __isset($key) {
    return isset($this->data[$key]);
  }
  /**
   * 以对象方式删除一个数组元素
   *
   * @access public
   * @param 数组元素键名
   */
  public function __unset($key) {
    unset($this->data[$key]);
  }
  /**
   * 以数组方式向data数组添加一个元素
   *
   * @access public
   * @abstracting ArrayAccess
   * @param string 偏移位置
   * @param mixed 元素值
   */
  public function offsetSet($offset,$value) {
    if (is_null($offset)) {
      $this->data[] = $value;
    } else {
      $this->data[$offset] = $value;
    }
  }
  /**
   * 以数组方式获取data数组指定位置元素
   *
   * @access public
   * @abstracting ArrayAccess
   * @param 偏移位置
   * @return mixed
   */
  public function offsetGet($offset) {
    return $this->offsetExists($offset) ? $this->data[$offset] : null;
  }
  /**
   * 以数组方式判断偏移位置元素是否设置
   *
   * @access public
   * @abstracting ArrayAccess
   * @param 偏移位置
   * @return boolean
   */
  public function offsetExists($offset) {
    return isset($this->data[$offset]);
  }
  /**
   * 以数组方式删除data数组指定位置元素
   *
   * @access public
   * @abstracting ArrayAccess
   * @param 偏移位置
   */
  public function offsetUnset($offset) {
    if ($this->offsetExists($offset)) {
      unset($this->data[$offset]);
    }
  }
}
$animal = new ArrayAndObjectAccess();
$animal->dog = &#39;dog&#39;; // 调用ArrayAndObjectAccess::__set
$animal[&#39;pig&#39;] = &#39;pig&#39;; // 调用ArrayAndObjectAccess::offsetSet
var_dump(isset($animal->dog)); // 调用ArrayAndObjectAccess::__isset
var_dump(isset($animal[&#39;pig&#39;])); // 调用ArrayAndObjectAccess::offsetExists
var_dump($animal->pig); // 调用ArrayAndObjectAccess::__get
var_dump($animal[&#39;dog&#39;]); // 调用ArrayAndObjectAccess::offsetGet
unset($animal[&#39;dog&#39;]); // 调用ArrayAndObjectAccess::offsetUnset
unset($animal->pig); // 调用ArrayAndObjectAccess::__unset
var_dump($animal[&#39;pig&#39;]); // 调用ArrayAndObjectAccess::offsetGet
var_dump($animal->dog); // 调用ArrayAndObjectAccess::__get
?>

Above output:

boolean true
boolean true
string 'pig' (length=3)
string 'dog' (length=3)
null
null

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