From: Todd Benson <caduceass@...>
Date: 2007-07-13T01:21:41+09:00
Subject: Re: XML file processing using REXML (beginner's question)

On 7/12/07, Ronald Fischer <ronald.fischer@venyon.com> wrote:
> Hello!
>
> I try to understand REXML using the tutorial in
>
>   http://www.germane-software.com/software/rexml/docs/tutorial.html
>
> However, I have problems applying the path expressions to my
> application.
> Consider for example the following program, and in particular the last
> line:
>
> #!/usr/bin/ruby
> require "rexml/document"
> require 'pp'
> source=<<ENDXML
> <ns:toplevel>
>      <ns:request requestID="1">
>         <ns:application aid="demo-a">
>          </ns:application>
>      </ns:request>
>      <ns:request requestID="2">
>         <ns:application aid="demo-b">
>         </ns:application>
>      </ns:request>
> </ns:toplevel>
> ENDXML
> doc=REXML::Document.new source
> doc.elements.each("ns:toplevel/ns:request") { |element| puts
> element.attributes["requestID"] }
> root=doc.root
> pp root.elements["ns:toplevel/ns:request[@requestID='2']"]
>
> The program outputs
>
> 1
> 2
> nil
>
> that is, it finds the two elements "request" and correctly outputs their
> attribute
> requestID, but when I try to locate request number two with the path
> expression
>
>   ns:toplevel/ns:request[@requestID='2']
>
> it is not found. What am I doing wrong here?

Your root variable represents your ns:toplevel so, either of these
would return an object instead of nil ...

pp root.elements["ns:request[@requestID='2']"]
pp doc.elements["ns:toplevel/ns:request[@requestID='2']"]

Todd