From: Farrel Lifson <farrel.lifson@...>
Date: 2006-08-07T05:46:21+09:00
Subject: Re: Method behaviour

On 06/08/06, Sard Aukary <sardaukary@yahoo.co.uk> wrote:
> Some methods like
>
> def change(word)
>         word[0]='e'
> end
> a="affluent"
> puts a
> change(a)
> puts a
>
> alter the original object outside of the method, where as others don't.
>
> def change(word)
>         word="fish"
> end
> a="cow"
> puts a
> change(a)
> puts a
>
>
> Why the change in behaviour, what determines it?  Is the only way I can
> write methods that change the original object by using the Ruby methods
> that do this?
>
> --
> Posted via http://www.ruby-forum.com/.
>
>

In the second example you are changing the reference to where 'word'
points. You create a new string ('fish') and then set 'word' to
reference it. 'a' still points to your original word ('cow').