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

sorry to post the question here but i haven't found it answered yet - i looked at the tutorials, faqs, q&a parts, made a search and still have no info so here it is 

 my hash is build in parsing an xml document (my $hash_name = XMLin($r
+esult);)
 if i print Dumper($hash_name{'element1'}->{'element2'}), i get :
 $VAR1 = {
          '365' => {
                     another hash of hashes ...
                   },
          '302' => {
                     another one 
                   }
        };

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the point is that i want to retrieve '365' and/or '302' - they are not preset values

i thought that doing 

my %tmp = $hash_name{'element1'}->{'element2'};

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and then using keys %tmp would give me those values, but it doesn't so please could someone help me ???

edit: Petruchio Tue Sep 18 11:55:13 UTC 2001 - Added markup

Replies are listed 'Best First'.
Re: hash of hashes of hashes ...
by davorg (Chancellor) on Sep 18, 2001 at 15:48 UTC

    (please learn how to format code readably with <code> tags)

    You should read perldoc perlreftut and perldoc perldsc for more explaination on this, but the basic solution to your problem is:

    my %tmp = %{$hash_name{'element1'}->{'element2'}};

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    --
    <http://www.dave.org.uk>

    Perl Training in the UK <http://www.iterative-software.com>

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Re: hash of hashes of hashes ...
by Zaxo (Archbishop) on Sep 18, 2001 at 15:59 UTC

    I'm a little uncertain of your formatting, I'll check back to see if I've misunderstood the question. Assuming $hash_name is a hashref, $hash_name->{'element1'}{'element2'} is a hashref to the data you want. To assign to a hash, dereference:

    my %tmp = %{$hash_name->{'element1'}{'element2'}};

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    You may not need the %tmp hash, that is a matter of convenience and depends on how much you need to manipulate the data.

    Update: Okay, I checked back. It's still unclear whether you have hash %hash_name or a hashref $hash_name. davorg's reply assumes the hash, supported by your usage of the arrow op. I assume a hashref because because of the form of its initial assignment. Checking, that's what XML::Simple's XMLin() returns. Are you using that module?

    After Compline,
    Zaxo

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      yes, i was using XML::Simple module
      and yes davorg's solution is working :)
      thank you SO MUCH :))
      and yes, i'll learn how to format my code, and re-read again and again the doc on references (i NEED to read it again and again ....)
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Re: hash of hashes of hashes ...
by graq (Curate) on Sep 18, 2001 at 16:35 UTC
    I will ignore the 'print Dumper' line and concentrate on your $VAR1 (which is a hash reference).

    My understanding of your question is:
    '365' and '302' are examples of keys in a hash whose hash values are a reference to a hash of hashes.

    To retrive the values '365' and '302' you need just use:

    my @hash_refs = keys %{$VAR1};

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    Then again, I could be misinterpreting your question!
    If you are still in doubt, post a useful code snippet.

    EXAMPLE 

    #!/usr/bin/perl -w
use strict;

my $VAR1 = { '365' => { foo=>1, bar=>2 }, '302' => {} };
my @hash_refs = keys %{$VAR1};

print "My hash refs are: ".join (', ',@hash_refs)."\n";
print "The value of my hash refs are: ".join(', ', values %{$VAR1})."\
+n\n";

my %tmp = %$VAR1;
print "'bar' in '365' is: ".$tmp{'365'}->{bar}."\n";

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    --
    Graq

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