如何选择具有某些属性的父节点

Question

如何选择具有某些属性的父节点.例如:什么是Xpath来选择所有expiration_time元素.在下面的XML中,如果states元素有属性,我会收到错误,否则没有probs.

谢谢

<lifecycle>
  <states elem="0">
    <expiration_time at="rib" zing="chack">08</expiration_time>
  </states>
  <states elem="1">
    <expiration_time  at="but">4:52</expiration_time>
  </states>
  <states elem="2">
    <expiration_time  at="ute">05:40:15</expiration_time>
  </states>
  <states elem="3">
    <expiration_time>00:00:00</expiration_time>
  </states>

</lifecycle>

Answer 1

states/expiration_time[../@elem = "0"]？