From: martindemello@... (Martin DeMello)
Date: 2002-10-22T05:34:47+09:00
Subject: Re: Grouping by twos

"Allen Mitchell" <ajm@nb.sympatico.ca> wrote in message news:<MHEFIIKIPJCFBKBGMHOGEEPPCOAA.ajm@nb.sympatico.ca>...
> I ran into the same requirement and I solved it by extending the Array
> class.  Have a look...

Neat. Getting positively verbose, but here's an extension to Enumerable

module Enumerable
  def eachn(n)
    a = []
    if block_given?
      each {|i| 
	a << i
	if a.length == n
	  yield a
	  a = []
	end
      }	
      yield a unless a.empty?    #possibly padded with nils
    else
      b = []
      eachn(n) {|i| b << i}
      b
    end
  end
end

a = (1..10).to_a
b = a.eachn(2)
puts a.inspect, # => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
     b.inspect  # => [[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]