From: Matthew Moss Date: 2006-02-04T02:07:24+09:00 Subject: Re: Allow additional parameters to Enumerable#inject Not really about inject specifically... just attempting another way a = [1,1,1,2,2,2,2,3,4,4,4,4] a.zip([0] + a).map { |i, j| i - j }.inject([]) do |s, k| k.zero? ? s[0...-1] + [s[-1] + 1] : s << k end