From: Rimantas Liubertas <rimantas@...>
Date: 2011-03-24T08:20:27+09:00
Subject: Re: iteration question

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/