访问 lxml.html 中输出的第一个元素

发布于 2024-09-15 21:50:23 字数 615 浏览 6 评论 0原文

使用 lxml.html，如何在不使用 for 循环的情况下访问单个元素？

这是 HTML：

<tr class="headlineRow">
  <td>
    <span class="headline">This is some awesome text</span>
  </td>
</tr>

例如，这将因 IndexError 而失败：

 for row in doc.cssselect('tr.headlineRow'):
     headline = row.cssselect('td span.headline')
     print headline[0]

这将通过：

 for row in doc.cssselect('tr.headlineRow'):
     headline = row.cssselect('td span.headline')
     for first_thing in headline:
         print headline[0].text_content()

原文

With lxml.html, how do I access single elements without using a for loop?

This is the HTML:

<tr class="headlineRow">
  <td>
    <span class="headline">This is some awesome text</span>
  </td>
</tr>

For example, this will fail with IndexError:

 for row in doc.cssselect('tr.headlineRow'):
     headline = row.cssselect('td span.headline')
     print headline[0]

This will pass:

 for row in doc.cssselect('tr.headlineRow'):
     headline = row.cssselect('td span.headline')
     for first_thing in headline:
         print headline[0].text_content()

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忱杏 2024-09-22 21:50:23

我通常使用 xpath 方法来处理这样的事情。
它返回匹配元素的列表。

>>> spans = doc.xpath('//tr[@class="headlineRow"]/td/span[@class="headline"]')
>>> spans[0].text
'This is some awesome text'

I usually use the xpath method for things like this.
It returns a list of matching elements.

>>> spans = doc.xpath('//tr[@class="headlineRow"]/td/span[@class="headline"]')
>>> spans[0].text
'This is some awesome text'

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绿光 2024-09-22 21:50:23

我使用 CSSSelector 和 headline[ 尝试了您的示例0] 工作正常。见下文：

>>> html  ="""<tr class="headlineRow">
  <td>
    <span class="headline">This is some awesome text</span>
  </td>
</tr>"""
>>> from lxml import etree
>>> from lxml.cssselect import CSSSelector
>>> doc = etree.fromstring(html)
>>> sel1 = CSSSelector('tr.headlineRow')
>>> sel2 = CSSSelector('td span.headline')
>>> for row in sel1(doc):
    headline = sel2(row)
    print headline[0]

<Element span at 8f31e3c>

I tried out your example using CSSSelector and headline[0] worked fine. See below:

>>> html  ="""<tr class="headlineRow">
  <td>
    <span class="headline">This is some awesome text</span>
  </td>
</tr>"""
>>> from lxml import etree
>>> from lxml.cssselect import CSSSelector
>>> doc = etree.fromstring(html)
>>> sel1 = CSSSelector('tr.headlineRow')
>>> sel2 = CSSSelector('td span.headline')
>>> for row in sel1(doc):
    headline = sel2(row)
    print headline[0]

<Element span at 8f31e3c>

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