From: Intransition <transfire@...>
Date: 2011-09-07T07:47:06+09:00
Subject: Grouping an array into sub-arrays.

Is there a method out there already that does anything like this?

    [0,1,2,3,4].group(0..-2, -1)  #=> [[0,1,2,3]. [4]]
    [0,1,2,3,4].group(0, 2..3, 4..-1)  #=> [[0], [2,3], [4]]