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问题描述

我找不到 Nokogiri 支持的 xpath 版本的官方声明.任何人都可以帮助我吗?事实上,我想提取一些具有以指定子字符串开头的属性的元素.例如,我想获取所有具有 category 属性以字符 C 开头的 Book 元素.如何用 nokogiri 做到这一点?

I can't find an official statement of the xpath version that Nokogiri supports. Anyone can help me with it? In fact I want to extract some elements that have an attribute start with specified sub string. For example, I want to get all Book elements that have a category attribute start with the character C. How to do this with nokogiri?

<?xml version="1.0" encoding="ISO-8859-1"?>
<!-- Edited by XMLSpy?-->
<bookstore>

<book category="COOKING">
  <title lang="en">Everyday Italian</title>
  <author>Giada De Laurentiis</author>
  <year>2005</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>

</bookstore>

推荐答案

我不知道 XPath Nokogiri 支持哪个特定版本.但是,您可以这样做:

I don't know which specific version of XPath Nokogiri supports. But, you can do this:

我想获取所有具有 category 属性以字符 C 开头的 book 元素.

使用 XPath 的 starts-with:

using XPath's starts-with:

doc = Nokogiri::XML(your_xml)
doc.search('//book[starts-with(@category, "C")]').each { |e| puts e['category'] }
# output is:
# COOKING
# CHILDREN

您也可以使用 CSS3 开头为"选择器:

You could also use a CSS3 "begins with" selector:

doc = Nokogiri::XML(your_xml)
doc.search('book[category^=C]').each { |e| puts e['category'] }
# output is:
# COOKING
# CHILDREN

这篇关于Nokogiri 支持哪个版本的 xpath?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!

09-05 12:18
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