提供像访问数组一样访问对象的能力的接口。

接口摘要

ArrayAccess {
    /* 方法 */
    abstract public boolean offsetExists ( mixed $offset )
    abstract public mixed offsetGet ( mixed $offset )
    abstract public void offsetSet ( mixed $offset , mixed $value )
    abstract public void offsetUnset ( mixed $offset )
}

实现接口

class obj implements arrayaccess {
    private $container = array();

    public function __construct() {
        $this->container = array(
            "one"   => 1,
            "two"   => 2,
            "three" => 3,
        );
    }
    public function offsetSet($offset, $value) 
    {
        if (is_null($offset)) {
            $this->container[] = $value;
        } else {
            $this->container[$offset] = $value;
        }
    }

    public function offsetExists($offset) 
    {
        return isset($this->container[$offset]);
    }

    public function offsetUnset($offset) 
    {
        unset($this->container[$offset]);
    }

    public function offsetGet($offset) 
    {
        return isset($this->container[$offset]) ? $this->container[$offset] : null;
    }
}

运行输出


$obj = new obj;

var_dump(isset($obj["two"])); # bool(true)

var_dump($obj["two"]); # int(2)

unset($obj["two"]); 
var_dump(isset($obj["two"])); # bool(false)

$obj["two"] = "A value";
var_dump($obj["two"]); # string(7) "A value"

$obj[] = 'Append 1';
$obj[] = 'Append 2';
$obj[] = 'Append 3';
print_r($obj);   
obj Object
(
    [container:obj:private] => Array
        (
            [one] => 1
            [three] => 3
            [two] => A value
            [0] => Append 1
            [1] => Append 2
            [2] => Append 3
        )

)