From: Aaron Patterson <aaron@...>
Date: 2010-07-05T13:35:12+09:00
Subject: Re: strange xpath output

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On Mon, Jul 05, 2010 at 11:00:38AM +0900, Pen Ttt wrote:
> /home/pt/jiexi  content is:
> <ul id=3D"ul_list">
> <li class=3D"expli"><a href=3D"tv_play-hdteleplay_20100211_7168444.html"
> title=3D"ok1"></a></li>
> <li><a href=3D"tv_play-hdteleplay_20100211_7168445.html"
> title=3D"ok2"></a></li>
> <li><a href=3D"tv_play-hdteleplay_20100211_7168446.html"
> title=3D"ok3"></a></li>
> <li><a href=3D"tv_play-hdteleplay_20100211_7168447.html"
> title=3D"ok4"></a></li>
> </ul>
>=20
> require 'rubygems'
> require 'nokogiri'
> doc =3D Nokogiri::HTML.parse(open('/home/pt/jiexi'))
> table=3Ddoc.xpath('//ul[@id=3D"ul_list"]/li/a')
> puts table
> output
> irb(main):005:0> puts table
> <a href=3D"tv_play-hdteleplay_20100211_7168444.html" title=3D"ok1"></a>
> <a href=3D"tv_play-hdteleplay_20100211_7168445.html" title=3D"ok2"></a>
> <a href=3D"tv_play-hdteleplay_20100211_7168446.html" title=3D"ok3"></a>
> <a href=3D"tv_play-hdteleplay_20100211_7168447.html" title=3D"ok4"></a>
> =3D> nil
> puts table.xpath('//ul')
> irb(main):006:0> puts table.xpath('//ul')
> <ul id=3D"ul_list">
> <li class=3D"expli"><a href=3D"tv_play-hdteleplay_20100211_7168444.html"
> title=3D"ok1"></a></li>
> <li><a href=3D"tv_play-hdteleplay_20100211_7168445.html"
> title=3D"ok2"></a></li>
> <li><a href=3D"tv_play-hdteleplay_20100211_7168446.html"
> title=3D"ok3"></a></li>
> <li><a href=3D"tv_play-hdteleplay_20100211_7168447.html"
> title=3D"ok4"></a></li>
> </ul>
>=20
> what i think is the  script "puts table.xpath('//ul')" will not create
> any output.
> how strange it is to  get the result,would  you mind to  tell me  why?

"//ul" says "find all ul tags anywhere in the document".  It looks like
you have a ul tag in your document, and the XPath is doing what it is
supposed to do.

Why would you expect "//ul" to have no results?

--=20
Aaron Patterson
http://tenderlovemaking.com/

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