php中foreach的使用

class MyClass

{

    public $var1 = 'value 1';

    protected $protected = 'protected var';

    private   $private   = 'private var';

    function iterateVisible()

    {

       foreach($this as $key => $value) {  //类内, foreach定义在成员方法;

       print "$key => $value\n";

       }

    }

}

$class = new MyClass();

foreach($class as $key => $value) {    //作为类外函数读取对象

print "$key => $value\n";

}                                  //var1 => value 1, 仅输出public属性

$class->iterateVisible()       //var1 => value 1, protected => protected var, private => private var 输出所有对象属性;