From: Tamreen Khan <tamreenkhan@...>
Date: 2007-01-17T04:15:23+09:00
Subject: Re: what is dup?

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On 1/16/07, Wilson Bilkovich <wilsonb@gmail.com> wrote:
>
> On 1/16/07, David Madden <moose56@gmail.com> wrote:
> > 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?
> >
>


I think a wordier but equivalent way of doing that is:
>
return self.dup.shuffle!

That just means "duplicate myself, shuffle the duplicate, then return it."

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