在PHP中知道类的命名空间的最简单方法是什么？ [重复]

Im wondering what is the easiest way to know the namespace of a class in PHP. For example I want to know the namespace of RecursiveArrayIterator.

</div>

$rc = new \ReflectionClass('CLASSPATH OR INSTANCE');
var_dump($rc->getNamespaceName());

Note: Empty string means global namespace