From: Joel VanderWerf <vjoel@...>
Date: 2005-06-18T08:57:27+09:00
Subject: Re: Why do arrays work this way?

Nigel Wilkinson wrote:
> Hi folks
> 
> I'm using ruby 1.8.2 as comes with Mandriva 2005LE and get the following 
> behaviour with arrays which doesn't seem logical to me.
> 
> In irb I do
> 
> irb(main):058:0* a=[1,2,3,4,5]
> => [1, 2, 3, 4, 5]
> 
> straight forward enough
> 
> irb(main):059:0> b=a
> => [1, 2, 3, 4, 5]
> irb(main):060:0> c=a
> => [1, 2, 3, 4, 5]
> 
> I've set 2 more variables to equal 'a'
> 
> irb(main):061:0> b[3] = 'w'
> => "w"
> 
> I believe this changes index 3 in'b' to now be equal to 'w'
> 
> do
> irb(main):062:0> b
> => [1, 2, 3, "w", 5]
> 
> that's exactly as I expected, BUT
> 
> irb(main):063:0> a
> => [1, 2, 3, "w", 5]
> irb(main):064:0> c
> => [1, 2, 3, "w", 5]
> 
> so what's the logic behind 'a' & 'c' changing when I change 'b'.

It's the same array in each case. The 3 variables each refer to it.