From: Robert Klemme <bob.news@...>
Date: 2005-10-30T21:52:21+09:00
Subject: Re: chain regex replacement

onurturgay@gmail.com wrote:
> hi,
> I want to make a chain replacement in my String object. For example
> a => b
> c => d
> f => k
>
> etc. Is there a way to make this replacement in one regex or something
> similar? I want to write a custom upcase downcase method, as the
> normal one doesnt support unicode (and ruby-unicode doesnt compile on
> windows).
>
> Thanks in advance
> onur

If you can make changes in one step, i.e. there is no change that will be 
changed later, you can use the block form of gsub:

str.gsub /[acf]/ do |m|
  case m[0]
    when ?a; "b"
    when ?c; "d"
    when ?f; "k"
    else raise "error"
  end
end

Kind regards

    robert