Array Ref Problem

jonjacobmoon has asked for the wisdom of the Perl Monks concerning the following question:

Maybe I am going about this wrong, but I think there should
be a way to do this.

I want to have a hash of array reference so I have the following 
code snippet:

<OUTSIDE LOOP>

    undef(@selections);

    while ((my $choice) = $sth->fetchrow_array())

      {

        push(@selections,$choice);

      }

    $selections{$_} = \@selections;

<END OUTSIDE LOOP>


The result of this is that when I undef the array to clear 
in preparation for the next iteration, I also undef the ref
from the previous iteration(s).  Then the next ref is created
and all values in the hash are the same reference which happens
to be the last reference used.

So, how do I build an array, put the ref into a hash and then 
loop back again so I can build up the next array to make a ref to 
put in the hash and so on.
[download]

Comment on Array Ref Problem Download Code

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(Ovid) Re: Array Ref Problem by Ovid (Cardinal) on Dec 29, 2001 at 04:52 UTC
Simplest is to drop the useless array. Also, you want `$sth->fetchrow_arrayref`. `while ((my $choice) = $sth->fetchrow_arrayref()) { push(@{ $selections{$_} },$choice); }` [download] Cheers, Ovid Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.	[reply] [d/l]
Re: (Ovid) Re: Array Ref Problem by jonjacobmoon (Pilgrim) on Dec 29, 2001 at 06:47 UTC
Right you are. Thanks.	[reply]
Re: Array Ref Problem by thor (Priest) on Dec 29, 2001 at 21:57 UTC
I also noticed the following: `while ((my $choice) = $sth->fetchrow_array())` You are fetching an array, but storing it in a scalar. You probably want to use the `fetchrow_arrayref` method. Keep in mind that you cannot simply push the array reference on to an array and hope to use it later, because as I understand it, that method reuses the same array reference on each fetch. In other words, you will get the same array many times when you try to dereference it.	[reply] [d/l] [select]
Re: Re: Array Ref Problem by jonjacobmoon (Pilgrim) on Jan 01, 2002 at 13:49 UTC
`Okay, here is it new's years eve and I am writting code. I think I should get extra XP just for that alone : ) Anyway, what I came up with was: <OUTER LOOP> { undef(@selections); while ((my $choice) = $sth->fetchrow_array()) { push(@{ $selections{$_} },$choice); } } <END OUTER LOOP> I tried that arrayref idea, but then I had to deference it again and it just seemed unnecessary unless I misunderstood what you were trying to say. Anyway, this all worked great and I thank all who helped out.` [download]	[reply] [d/l]