获取子节点包含属性的节点 [英] Get nodes where child node contains an attribute

问题描述

假设我有以下 XML:

Suppose I have the following XML:

<book category="CLASSICS">
  <title lang="it">Purgatorio</title>
  <author>Dante Alighieri</author>
  <year>1308</year>
  <price>30.00</price>
</book>

<book category="CLASSICS">
  <title lang="it">Inferno</title>
  <author>Dante Alighieri</author>
  <year>1308</year>
  <price>30.00</price>
</book>

<book category="CHILDREN">
  <title lang="en">Harry Potter</title>
  <author>J K. Rowling</author>
  <year>2005</year>
  <price>29.99</price>
</book>

<book category="WEB">
  <title lang="en">XQuery Kick Start</title>
  <author>James McGovern</author>
  <author>Per Bothner</author>
  <author>Kurt Cagle</author>
  <author>James Linn</author>
  <author>Vaidyanathan Nagarajan</author>
  <year>2003</year>
  <price>49.99</price>
</book>

<book category="WEB">
  <title lang="en">Learning XML</title>
  <author>Erik T. Ray</author>
  <year>2003</year>
  <price>39.95</price>
</book>

我想做一个 xpath 来取回所有具有标题节点且语言属性为it"的书籍节点.

I would like to do an xpath that gets back all book nodes that have a title node with a language attribute of "it".

我的尝试看起来像这样:

My attempt looked something like this:

//book[title[@lang='it']]

但这没有用.我希望取回节点:

But that didn't work. I expect to get back the nodes:

<book category="CLASSICS">
  <title lang="it">Purgatorio</title>
  <author>Dante Alighieri</author>
  <year>1308</year>
  <price>30.00</price>
</book>

<book category="CLASSICS">
  <title lang="it">Inferno</title>
  <author>Dante Alighieri</author>
  <year>1308</year>
  <price>30.00</price>
</book>

有什么提示吗?

推荐答案

尝试

//book[title/@lang = 'it']

内容如下:

• 获取所有 book 元素
  • 至少有一个title
    • 有一个属性 lang
      • 值为 "it"

      您可能会发现 this 很有帮助 — 这是一篇名为 五段中的 XPath" 作者:Ronald Bourret.

      You may find this helpful — it's an article entitled "XPath in Five Paragraphs" by Ronald Bourret.

      但老实说，//book[title[@lang='it']] 和上面的应该是等价的，除非您的 XPath 引擎有问题".因此，它可能是您没有向我们展示的代码或示例 XML 中的某些内容——例如，您的示例是一个 XML 片段.是否可能是根元素有一个命名空间，而您没有在查询中计算它?你只告诉我们它没有用，但你没有告诉我们你得到了什么结果.

      But in all honesty, //book[title[@lang='it']] and the above should be equivalent, unless your XPath engine has "issues." So it could be something in the code or sample XML that you're not showing us -- for example, your sample is an XML fragment. Could it be that the root element has a namespace, and you aren't counting for that in your query? And you only told us that it didn't work, but you didn't tell us what results you did get.

      这篇关于获取子节点包含属性的节点的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！