From: Robert Klemme <shortcutter@...>
Date: 2008-08-02T17:54:01+09:00
Subject: Re: Gsup with variable when replacing

On 28.07.2008 14:51, Sebastian Hungerecker wrote:
> Romain LOMBARDO wrote:
>> f3 = line.gsub!(/\d+$/,'<number>\1</number>')
> 
> \1 means "first group", but there are no groups in your regex. \0 means "whole 
> match", so that's the one you want.

I wasn't aware that \0 does the job as well.  I always use \& for the 
whole match.  Learn something new every day. :-)

> Another thing: gsub! is the mutating variant of gsub. It will return nil when 
> no change occurs or self when there is a change. Either way it does not make 
> sense to store its return value.
> And yet another thing: there is no sense in using gsub (as opposed to sub) 
> with a regex that only matches once anyway.

Absolutely.

Another remark, iterating through a file can be made easier:

File.foreach("D:/digisoft/1b.txt") do |line|
   line.gsub!(/\d+$/,'<number>\\&</number>')
   puts line
end

Kind regards

	robert