From: Robert Klemme <shortcutter@...>
Date: 2011-11-24T21:49:32+09:00
Subject: Re: NOKIGIRI XPATH

2011/11/24 Jesús Gabriel y Galán <jgabrielygalan@gmail.com>:
> On Thu, Nov 24, 2011 at 12:30 PM, Ruby Mania <prateek123@gmail.com> wrote:
>> Thanks a lot for help. But it matched CDEF and all nodes after that even
>> if key != english
>
> I'm not sure why is this. I'm still trying to come up with a good
> XPath that will return just that node,

Well, there could be many matches and from the original posting I
cannot see that only the first is needed.

> but in the meantime you can do this:
>
> doc.xpath("//key[. = 'English']/following-sibling::topic/data")[0]

Or better

doc.at_xpath("//key[. = 'English']/following-sibling::topic[1]/data")

I would probably do

doc.xpath('//topic[preceding-sibling::key[text()="English"]]//data')

or, for one hit only

doc.at_xpath('//topic[preceding-sibling::key[text()="English"]][1]//data')

Not sure about efficiency but I prefer it visually to have the path to
the selected node as basis and use criteria in [] for filtering.

If we want to be even more robust we could do

doc.xpath('//topic[preceding-sibling::key[last() and text()="English"]]//data')

This will avoid matching the topic in

<key>English</key>
...
<key>Foo</key>
<topic>...

or

<key>English</key>
<another>...</another>
<topic>

Kind regards

robert


PS: My favorite XPath help
http://www.w3schools.com/xpath/default.asp
http://www.zvon.org/xxl/XPathTutorial/General/examples.html

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/