From: Jano Svitok <jan.svitok@...>
Date: 2008-01-09T23:48:51+09:00
Subject: Re: Why this behaviour?

On Jan 9, 2008 3:35 PM, Daniele Antani <daniele.cesarini@gmail.com> wrote:
> Hello to all,
>
> i can't understand the follow behaviour:
>
> class Player
>   attr_accessor :hand
>   def initialize(hand)

This copies reference to the array, use #dup to create a copy (note
that it's not recursive):
-      @hand = hand
+     @hand = hand.dup

>   end
> end
>
> def roba(player)
>   p2 = Player.new(player.hand)
>   change p2
>   print "p2 = "
>   p p2
>   print "player = "
>   p player
> end
>
> def change(player)
>   player.hand.push(3)
> end
>
>
> p1 = Player.new([2, 3, 4])
> roba p1
>
> __END__
>
> output is:
> p2 = #<Player:0xb7c4919c @hand=[2, 3, 4, 3]>
> player = #<Player:0xb7c491c4 @hand=[2, 3, 4, 3]>
>
>
> Why the change affects both objects? I want to copy the first object and
> work on the copy without affecting the original.
>
> Thanks
> --
> Posted via http://www.ruby-forum.com/.
>
>