From: why the lucky stiff <ruby-talk@...>
Date: 2005-08-19T03:25:07+09:00
Subject: Re: Idiomatic ruby version of this code?

Brock Weaver wrote:
> Here's my first solution:
>
> Dir.new("./").each do |file|
> 	if file.match(/mp3$/)
> 		File.rename(file, file.gsub(/mp3$/, 'temp'))
> 	elsif file.match(/temp$/)
> 		File.rename(file, file.gsub(/temp$/, 'mp3'))
> 	end
> end
>   
You could use the tertiary operator to switch file names, but the (exp 
.. and .. or) is also nice for this kind of swapping thing.

  Dir["*.{temp,mp3}"].each do |file|
    File.rename( file, file.gsub( /\w+$/ ) { |ext| ext == 'mp3' and 
'temp' or 'mp3' } )
  end

If you don't want your extensions hardcoded everywhere, use an array:

  exts = ['temp', 'mp3']
  Dir["*.{#{exts.join ','}}"].each do |file|
    File.rename( file, file.gsub( /(\w+)$/ ) { exts.detect { |x| x != $1 
} } )
  end

_why