From: Axel Etzold <AEtzold@...>
Date: 2008-09-08T04:20:47+09:00
Subject: Re: regular expression match and exclude


-------- Original-Nachricht --------
> Datum: Mon, 8 Sep 2008 02:46:12 +0900
> Von: Azalar --- <pteale@gmail.com>
> An: ruby-talk@ruby-lang.org
> Betreff: Re: regular expression match and exclude

> 
> I should mention that image isn't a fixed word in this case I just used 
> that as an example.
> It represents whatever the name of the image is
> 
> So the test data could be..
> 
> galleries/blah.jpg
> galleries/blahthumb.jpg
> galleries/landscape.jpg
> galleries/landscapethumb.jpg
> galleries/foo.jpg
> galleries/foothumb.jpg
> 
> 
> Robert Klemme wrote:
> > 2008/9/7 Azalar --- <pteale@gmail.com>:
> >>
> >> The array is created when i use the scan method so if i used reject it
> >> would become a two pass process which is what i am doing anyway so I
> was
> >> wondering if regular expressions had built in support for this.
> > 
> > Will be hard.  It's easier if you do
> > 
> > %r{galleries/image\d+\.jpg\z}
> > 
> > Kind regards
> > 
> > robert
> 
> -- 
> Posted via http://www.ruby-forum.com/.

Dear Azalar,

to achieve searching for some text pattern that is not followed by something else, you need
regular expressions with negative lookahead

http://www.regular-expressions.info/lookaround.html

As far as I know, this is not supported by Ruby's 1.8.x regexps, but there is a special library, Oniguruma,
with Ruby bindings available for this.

http://oniguruma.rubyforge.org/

Best regards,

Axel 
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