Two-dimensional hash problem

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

What's wrong with this 2-dimensional hash? It says that $gra{$k} is not a hash, but it should be the other dimension of the hash. Any ideas what I'm doing wrong?

my %gra;
$gra{"test"}{"A"}=44;
$gra{"test"}{"B"}=41;
$gra{"foo"}{"A"}=43;
for my $k (keys %gra) {
        print $k,"\n";
        for my $i (keys $gra{$k}) {
              my $v=$gra{$k}{i};
              print "$i: $v\n";
        }
}
[download]

Comment on Two-dimensional hash problem Download Code

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Re: Two-dimensional hash problem by diotalevi (Canon) on Nov 04, 2005 at 21:39 UTC
$gra{$k} is a reference, not a hash. Enclose it in %{...} like %{$gra{$k}}.	[reply]
Re: Two-dimensional hash problem by Tanktalus (Canon) on Nov 04, 2005 at 21:40 UTC
First thing I notice is the lack of $ in the {i} on the fourth-last line (first line inside the inner for loop). Second thing I notice is your indentation. It's a bit much. Third thing I notice is that keys requires a hash, not a hash ref. The inner for loop should be: `for my $i (keys %{$gra{$k}})` [download] You need to dereference that reference.	[reply] [d/l]
Re^2: Two-dimensional hash problem by nyk (Novice) on Nov 04, 2005 at 21:46 UTC
Thanks a lot! The "i" instead of "$i" was a mistake when I simplified the problem from my code for the this forum, I know it's wrong.	[reply]