Help dereferencing a data structure

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

I have a data structure which resembles:

$VAR1 = {
          'key' => {
                          'data' => [
                                      [
                                        'Element1',
                                        'Element2',
                                        'Element3'
                                      ],
                                      [
                                        'Element1',
                                        'Element2',
                                        'Element3'
                                      ]
                                    ]
                        }
[download]

How can I iterate over the anonymous array in the data value? I thought this would work, but it doesn't:

for my $elmt (@{$book->{$key}{data}}) {
    ....
}
[download]

Comment on Help dereferencing a data structure Select or Download Code

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Re: Help dereferencing a data structure by NetWallah (Canon) on Mar 27, 2008 at 05:47 UTC
You have a reference to a HOHOAOA, and need to de-reference it so: `use strict; use warnings; my $book = { 'key' => {'data' => [ [ 'Element1', 'Element2', 'Element3' ], [ 'Element1', 'Element2', 'Element3' ] ] } }; for my $key (keys %$book){ for my $data ( keys %{ $book->{$key} } ){ for my $inner_array_ref ( @{ $book->{$key}{$data} } ) { ## Array above can also be written as: @{ $book->{$key}-> +{$data} } print "$key\t$data\t@$inner_array_ref\n"; } } }` [download] "As you get older three things happen. The first is your memory goes, and I can't remember the other two... " - Sir Norman Wisdom	[reply] [d/l]
Re: Help dereferencing a data structure by planetscape (Chancellor) on Mar 27, 2008 at 09:32 UTC
Please see: intro to references References quick reference You may also find: How can I visualize my complex data structure? Re: I've got a hash of hashes how do i get my values out helpful. HTH, planetscape	[reply]
Re: Help dereferencing a data structure by wade (Pilgrim) on Mar 27, 2008 at 04:08 UTC
There are a couple issues. One is that you had references and you treated one as a hash. Also, I think you meant "key" when you used $key (of course, if `$key eq "key"`...). This code seems to work. `use strict; use warnings; { foreach my $datum (@{$var1->{"key"}->{"data"}->[0]}) { print "$datum\n"; } }` [download] -- Wade	[reply] [d/l] [select]