From: Hal Fulton <hal9000@...>
Date: 2004-04-27T09:20:58+09:00
Subject: Re: The Strangeness of Arrays

Roger Bannister wrote:
> Hi
> 
> The behaviour below has me completely confuzzled. Why on earth does my 
> array suddenly have all rows equal to the last row?
> 
> Can anyone tell me if this is expected; or if I have to start wearing my 
> Stupid Hat again.

It's the strangeness of objects, not arrays. See below...

> Thanks
> R
> 
> irb(main):014:0> @t = Array.new(5, Array.new(4))

This fills @t with five references to the same four-item array.

If you change one, you change them all.

I think in recent Ruby you can do this:

   @t = Array.new(5) { Array.new(4) }

and you'll get different sub-arrays. Try it...


Hal