From: Martin DeMello <martindemello@...>
Date: 2003-11-21T01:12:33+09:00
Subject: Re: learning the "Ruby way"

Mark Wirdnam <mark.wirdnam@stud.unibas.ch> wrote:
> 
> Problem:
> I have a sorted list ('alfred', 'boris', 'bruce', 'claire', 'dean', 'donald')
> and would like to generate or return ('-a-', 'alfred', '-b-', 'boris',
> 'bruce', '-c-', 'claire', '-d-', 'dean', 'donald').

One more way to do it...

require 'enum/cluster' # http://redshift.sourceforge.net/enum

lst = ['alfred', 'boris', 'bruce', 'claire', 'dean', 'donald']

a = ["--#{lst[0][0..0]}--"]
lst.each_cluster(2) {|i, j|
  a << i
  a << "--#{j[0..0]}--" if i[0] != j[0]
}

p a

martin