没有具有相同属性的祖先的属性的 xPath 表达式 [英] xPath expression for attributes that don't have ancestors with same attribute
问题描述
我试图提取具有属性的元素，而不是单独提取具有相同属性的后代.
使用以下 html:
<div 框>一些文字<div 框>还有一些文字<div 框>这也需要包括在内
</body></html>
我希望能够提取两个外部
，但不想单独提取内部 .我尝试过使用各种不同的表达方式，但我认为我遗漏了一些非常基本的东西.我一直在尝试的主要表达式是: //[@box and not(ancestor::@box) 但这仍然返回两个元素.
我正在尝试使用 Ruby 1.9.2 中的Hpricot"(0.8.3) Gem 来执行此操作，如下所示:
#假设html设置为上面的htmldoc = Hpricot(html)element = doc.search('//[@box 而不是(ancestor::@box)]')# 以下是返回 3 而不是 2元素大小
对此的任何帮助都会很棒.
解决方案 您的 XPATH 无效.您必须解决某些问题才能使用谓词过滤器(例如 []).否则，没有任何东西可以过滤.
此 XPATH 有效:
//div[@box and not(ancestor::div/@box)]
如果元素不能全部保证为
，您可以对元素使用更通用的匹配://*[@box and not(ancestor::*/@box)]
I'm trying to extract elements with an attribute, and not extract the descendants separately that have the same attribute.
Using the following html:
<html><body>
<div box>
some text
<div box>
some more text
</div>
</div>
<div box>
this needs to be included as well
</div>
</body></html>
I want to be able to extract the two outer <div box> and its descendants including the inner <div box>, but don't want to have the inner <div box> extracted separately.
I have tried using all sorts of different expressions but think I am missing something quite fundamental. The main expression I have been trying is: //[@box and not(ancestor::@box) but this still returns two elements.
I am trying to do this using the 'Hpricot' (0.8.3) Gem in Ruby 1.9.2 as follows:
# Assuming html is set to the html above
doc = Hpricot(html)
elements = doc.search('//[@box and not(ancestor::@box)]')
# The following is returning 3 instead of 2
elements.size
Any help on this would be great.
解决方案 Your XPATH is invalid. You have to address something in order to use the predicate filter(e.g. []). Otherwise, there isn't anything to filter.
This XPATH works:
//div[@box and not(ancestor::div/@box)]
If the elements aren't all guarenteed to be <div>, you can use a more generic match for elements:
//*[@box and not(ancestor::*/@box)]
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