XPATH选择所有不为空的子级，并在找不到时添加默认值

Question

是否存在XPATH返回所有非空someChild以及在找不到on值时的默认值？

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

我想得到：

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

或

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

Answer 1

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

为避免违反“ /”的RHS无法选择节点和原子值的混合的规则，请仔细编写此代码。在3.0中，您可以使用“！”运算符：

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

Answer 2

尝试以下表达式：

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