From: Roger Bannister <rdb@...>
Date: 2004-04-27T09:27:03+09:00
Subject: Re: The Strangeness of Arrays

Hal Fulton wrote:

> 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
>
>
>
>
Right, it's the hat for me! I'd completely forgotten the basic example 
of a = 1; b = a.

Thanks guys.