From: bbiker <renard@...>
Date: 2011-03-24T10:20:29+09:00
Subject: Re: iteration question

On Mar 23, 7:20 pm, Rimantas Liubertas <riman...@gmail.com> wrote:
> data = Array.new(5,[])
> This gives you array with five references to the same array object:
>
> ruby-1.9.2-p0 :036 > data = Array.new(5,[])
> => [[], [], [], [], []]
>
> ruby-1.9.2-p0 :037 > data[0].object_id
> => 2156232780
> ruby-1.9.2-p0 :038 > data[1].object_id
> => 2156232780
>
> > 0.upto(4) do |i|
> > data[i].push(i)
>
> no matter where you push you are still pushing to the same single array
>
> What you want probably is:
>
> data = Array.new(5) {[]}
> 0.upto(4) do |i|
> data[i].push(i)
> end
> p data
>
> In this case it is the same as
>
> data = Array.new(5) {|index| [index]}
> => [[0], [1], [2], [3], [4]]
>
> Regards,
> Rimantas
> --http://rimantas.com/

Alternate way of doing the same thing:

data = []
0.upto(4) { |i| data << [i] }

regards,
 bbiker