From: David Madden Date: 2007-01-17T02:26:03+09:00 Subject: what is dup? I am playing with an example in the ruby cookbook where a shuffle function is added to the array class: class Array def shuffle! each_index do |i| j = rand(length-i) + i self[j], self[i] = self[i], self[j] end end def shuffle dup.shuffle! end end What I don't understand is the line "dup.shuffle!" What is the dup object? Dave.