php foreach（）循环数组遍历问题。求解。

[user] => SimpleXMLElement Object
(
[avatar] => http://img.taobaocdn.com/sns_logo/T1GVlAXs8bXXb1upjX.jpg
[buyer_credit] => SimpleXMLElement Object
(
[good_num] => 171
[level] => 5
[score] => 171
[total_num] => 171
)
[nick] => youyu63158
[sex] => SimpleXMLElement Object
(
)
)
请问我如何在 [user] 的数组下将字段为[buyer_credit]的数组遍历出来呢、怎么写详细点。。
SimpleXMLElement Object
(
[user] => SimpleXMLElement Object
(
[avatar] =>http://img.taobaocdn.com/sns_logo/T1GVlAXs8bXXb1upjX.jpg
[buyer_credit] => SimpleXMLElement Object
(
[good_num] => 171
[level] => 5
[score] => 171
[total_num] => 171
)
[nick] => youyu63158
[sex] => SimpleXMLElement Object (　)
)
)
对象里的一个数组

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