如何访问php大括号对象属性

Question

可能重复:
如何使用整数等名称访问对象属性？

print_r($myObj) 给出以下结果:

stdClass Object
(
    [4021450] => stdClass Object
    (
        [property1] => ooo
        [property2] => xxx
    )
    [3971601] => stdClass Object
    (
        [property1] => 123
        [property2] => 356
    )
)

如何使用大括号语法和变量来访问sub-object？

我试过了:

$myObj->'3971601';                     // Parse error: syntax error  
$myObj->{'3971601'};                   // Works  
$id = 3971601; $myObj->{$id};          // Notice: Trying to get property of non-object  
$id = 3971601; $myObj->{''.$id};       // Notice: Trying to get property of non-object  
$arr = (array)$myObj; $arr[3971601];   // Notice: Undefined offset: 3971601
$arr = (array)$myObj; $arr['3971601']; // Notice: Undefined index: 3971601