如何使用 XPath 查找一组元素中某个属性的最小值? [英] How can I use XPath to find the minimum value of an attribute in a set of elements?

问题描述

如果我有像这样的 XML:

If I have XML like:

<foo>
  <bar id="1" score="192" />
  <bar id="2" score="227" />
  <bar id="3" score="105" />
  ...
</foo>

我可以使用 XPath 查找 score 的最小值和最大值吗?

Can I use XPath to find the minimum and maximum values of score?

编辑:我使用的工具(Andariel 蚂蚁任务)没有不支持 XPath 2.0 解决方案.

Edit: The tool i'm using (Andariel ant tasks) doesn't support the XPath 2.0 solution.

推荐答案

原来该工具不支持 XPath 2.0.

Turns out the tool does not support XPath 2.0.

XPath 1.0 没有花哨的 min() 和 max() 函数，所以要找到这些值，我们需要对 XPath 逻辑有点棘手，并比较节点的兄弟节点上的值:

XPath 1.0 doesn't have the fancy min() and max() functions, so to find these values we need to be a little tricky with the XPath logic, and compare the values on the siblings of the node:

最大值:

/foo/bar[not(preceding-sibling::bar/@score >= @score) 
    and not(following-sibling::bar/@score > @score)]/@score

最低:

/foo/bar[not(preceding-sibling::bar/@score <= @score) 
    and not(following-sibling::bar/@score < @score)]/@score

如果将这些查询嵌入 XSLT 或 ant 脚本等 XML 文件中，请记住将 < 和 > 编码为 < 尊重 >.

If embedding these queries in XML files like XSLT or ant scripts, remember to encode < and > as < respecting >.

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