From: James Edward Gray II <james@...>
Date: 2006-01-17T11:41:44+09:00
Subject: Re: Question about regular expression

On Jan 16, 2006, at 8:35 PM, Eric Luo wrote:

> I need to hack out an regular expression, which will match "SNPB"  
> without
> matching "STR SNPB".
> Since ruby 1.8.2 or 1.8.4 don't support the  lookbehind feature.  
> what's the
> workable regular expression
> for ruby version 1.8.2?

Lookbehind is just lookahead, backwards.  ;)

 >> tests = %w{SNPB STR\ SNPB}
=> ["SNPB", "STR SNPB"]
 >> tests.map { |t| t.reverse }.grep(/\bBPNS\b(?! RTS)/).map { |t|  
t.reverse }
=> ["SNPB"]

Hope that helps.

James Edward Gray II