是否可以找到< td> ..</td> </td>中的任何一个.价值是已知的吗? [英] Is it possible to find the <td> .. </td> text, when any of the <td>..</td> value is known?

问题描述

我有一个网页，其网页格式与html相似，如下所示:

I have an webpage which has the similar kind of html format as below:

<form name="test">

<td> .... </td>
  .
  .
  .
<td> <A HREF="http://www.edu/st/file.html">alo</A> </td>
<td> <A HREF="http://www.dom/st/file.html">foo</A> </td>
<td> bla bla </td>

</form>

现在，我只知道值bla bla，基于该值我们可以跟踪或找到3rd last ..值(此处为alo)吗?我可以在HREF值的帮助下跟踪这些值，但是HREF值并不总是固定的，它们可以随时为任意值.

Now, I know only the value bla bla, base on the value can we track or find the 3rd last .. value(which is here alo)? I can track those,with the help of HREF values,but the HREF values are not fixed always, they can be anything anytime.

推荐答案

从HTML文档中提取每个<td>都很容易，但这并不是浏览DOM的可靠方法.但是，鉴于示例HTML的局限性，这是一个解决方案.我怀疑它是否可以在实际情况下工作.

Extracting every <td> from an HTML document is easy, but it's not a foolproof way to navigate the DOM. However, given the limitations of the sample HTML, here's a solution. I doubt it'll work in a real-world situation though.

Mechanize在内部使用Nokogiri进行繁重的工作，因此如果您已经需要Mechanize，则无需执行require 'nokogiri'.

Mechanize uses Nokogiri internally for its heavy lifting so doing require 'nokogiri' isn't necessary if you've already required Mechanize.

require 'nokogiri'

doc = Nokogiri::HTML::DocumentFragment.parse(<<EOT)
<td> <A HREF="http://www.edu/st/file.html">alo</A> </td>
<td> <A HREF="http://www.dom/st/file.html">foo</A> </td>
<td> bla bla </td>
EOT

doc.search('td')[-3].at('a')['href']
=> "http://www.edu/st/file.html"

如何练习如何从机械化代理"获取Nokogiri文档作为用户的练习.

How to get the Nokogiri document from the Mechanize "agent" is left as an exercise for the user.

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