得到 House 中的所有房间（无论位置如何）

XML

<House>
    <numRooms>4</numRooms>
    <Floor number="1">
        <Room name="living"/>
        <Room name="kitchen"/>
    </Floor>
    <Floor number="2">
        <Room name="master bedroom"/>
        <Room name="kids' bedroom"/>    
    </Floor>
</House>

XPATH

/House/descendant::Room

OUTPUT

<Room name="living" />
<Room name="kitchen" />
<Room name="master bedroom" />
<Room name="kids' bedroom" />