flatten.rb

2.1.5 :027 > def flatten a
2.1.5 :028?>     flat = []
2.1.5 :029?>     a.each{|i| i.is_a?(Array) ? flat += flatten(i) : flat << i }
2.1.5 :030?>     return flat
2.1.5 :031?>   end
 => :flatten
2.1.5 :032 > flatten [1,2,[:a,:b,:c],3,4]
 => [1, 2, :a, :b, :c, 3, 4]
2.1.5 :033 >