XPATH选择所有非空子项加上未找到时的默认值

Question

是否有XPATH返回所有非null someChild加上未找到值的默认值？

<someFather>
    <someChild/>
    <someChild/>
    <someChild>some value</someChild>
    <someChild/>
    <someChild>some other value</someChild>
    <someChild/>
</someFather>

我想得到：

""
""
some value
""
some other value
""

， 要么

"not-found"
"not-found"
some value
"not-found"
some other value
"not-found"

Answer 1

请尝试以下表达式：

/someFather/(someChild/string(), '') 

Answer 2

/someFather/someChild/(text()/string(), "not-found")[1]

这是经过仔细编写的，以避免违反“/”的RHS不能选择节点和原子值的混合的规则。在3.0中你可以使用“！”运营商：

/someFather/someChild ! (text(), "not-found")[1]