php 迭代 遍曆對象

    class A{
        public $v1 = 'public var1';
        public $v2 = 'public var2';
        protected $v3 = 'protected var3';
        private $v4 = 'private var4';

        public function iterateVisuable(){        //遍曆對象成員的方法
            foreach($this as $key => $value){
                echo "$key => $value";
                echo "/n";
            }
        }
    }

    $a = new A();
    foreach($a as $key => $value){     //類外遍曆對象成員
        echo '$key'.'=>'."$value";
        echo "/n";
    }

    $a->iterateVisuable();
?>
    //總之，所有可見的成員都可以在迭代中被訪問