strange xpath output

[Pen Ttt]

/home/pt/jiexi content is:
<ul id="ul_list">
<li class="expli"><a href="tv_play-hdteleplay_20100211_7168444.html"
title="ok1"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168445.html"
title="ok2"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168446.html"
title="ok3"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168447.html"
title="ok4"></a></li>
</ul>

require 'rubygems'
require 'nokogiri'
doc = Nokogiri::HTML.parse(open('/home/pt/jiexi'))
table=doc.xpath('//ul[@id="ul_list"]/li/a')
puts table
output
irb(main):005:0> puts table
<a href="tv_play-hdteleplay_20100211_7168444.html" title="ok1"></a>
<a href="tv_play-hdteleplay_20100211_7168445.html" title="ok2"></a>
<a href="tv_play-hdteleplay_20100211_7168446.html" title="ok3"></a>
<a href="tv_play-hdteleplay_20100211_7168447.html" title="ok4"></a>
=> nil
puts table.xpath('//ul')
irb(main):006:0> puts table.xpath('//ul')
<ul id="ul_list">
<li class="expli"><a href="tv_play-hdteleplay_20100211_7168444.html"
title="ok1"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168445.html"
title="ok2"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168446.html"
title="ok3"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168447.html"
title="ok4"></a></li>
</ul>

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?

 

[Robert Klemme]

/home/pt/jiexi content is:
<ul id="ul_list">
<li class="expli"><a href="tv_play-hdteleplay_20100211_7168444.html"
title="ok1"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168445.html"
title="ok2"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168446.html"
title="ok3"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168447.html"
title="ok4"></a></li>
</ul>

require 'rubygems'
require 'nokogiri'
doc = Nokogiri::HTML.parse(open('/home/pt/jiexi'))
table=doc.xpath('//ul[@id="ul_list"]/li/a')
puts table
output
irb(main):005:0> puts table
<a href="tv_play-hdteleplay_20100211_7168444.html" title="ok1"></a>
<a href="tv_play-hdteleplay_20100211_7168445.html" title="ok2"></a>
<a href="tv_play-hdteleplay_20100211_7168446.html" title="ok3"></a>
<a href="tv_play-hdteleplay_20100211_7168447.html" title="ok4"></a>
=> nil
puts table.xpath('//ul')
irb(main):006:0> puts table.xpath('//ul')
<ul id="ul_list">
<li class="expli"><a href="tv_play-hdteleplay_20100211_7168444.html"
title="ok1"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168445.html"
title="ok2"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168446.html"
title="ok3"></a></li>
<li><a href="tv_play-hdteleplay_20100211_7168447.html"
title="ok4"></a></li>
</ul>

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?

That's perfectly expected. If you look closely at the eplanation,
you'll find out:

http://www.w3schools.com/Xpath/xpath_syntax.asp

You probably wanted

puts table.xpath('ul')

Kind regards

robert