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

Blessed Perl monks, I've been on this problem for 6 hours now and I must submit. I need help. I'm trying to dereference a complex data structure and can't seem to figure it out. The data structure is referenced by a global variable: $IN Doing Data::Dumper($IN) yields: 
$VAR1 = bless( {
                 'data_loaded' => 1,
                 'params' => {},
                 'cookies' => {
                                'Community_Sesssion' => [
                                                          '68ce4195515
+b8040f9174503dacfe200'
                                                        ],
                                'PHPSESSID' => [
                                                 'e09347f6ca73f155b1fd
+6500e92302b8'
                                               ],
                                '__utmb' => [
                                              '248415237'
                                            ],
                                
                                '__utmc' => [
                                              '248415237'
                                            ],
                               
                                '__qcb' => [
                                             '608960055'
                                           ],

                                '__qca' => [
                                             '1234223794-30138386-6175
+0767'
                                           ]
                              },
                 'p' => '',
                 'nph' => 0,
                 '_debug' => 0
               }, 'GT::CGI' );

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What I'm trying to do is iterate through all the values of the cookies hash and do something with them. The last think I tried (out of about 100 other ways) is: 

        my %cookie_hash = $IN->{cookies};

    foreach my $group (keys %cookie_hash) {
        print "The members of $group are\n";
        foreach (@{$cookie_hash{$group}}) {
            print "\t$_\n";
        }
    }

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This outputs: 
The members of HASH(0x828b958) are

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Honestly, I'm stumped... Any help would be greatly appreciated.. Mike

Replies are listed 'Best First'.
Re: Dereferencing my hash?
by Fletch (Bishop) on Feb 10, 2009 at 20:03 UTC

    If you were running with warnings you would have gotten griped at for my %cookie_hash = $IN->{cookies};. To make a copy of a hashref into a hash you need to dereference it first: my $hash = %{ $hash_ref };

    The cake is a lie.
    The cake is a lie.
    The cake is a lie.

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Re: Dereferencing my hash?
by Bloodnok (Vicar) on Feb 10, 2009 at 20:04 UTC
    I take it you haven't got strictures (use warnings; use strict;) enabled.

    Had you done so, you would probably have been able to tell that, in 

    my %cookie_hash = $IN->{cookies};

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    , you are attempting to assign a hash ref. to a hash (perlref)... try either 
    my %cookie_hash = %{ $IN->{cookies} };

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    or, the more usual, 
    my $cookie_hash = $IN->{cookies};

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    ...

    A user level that continues to overstate my experience :-))
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Re: Dereferencing my hash?
by jethro (Monsignor) on Feb 10, 2009 at 20:07 UTC 
    foreach my $group (keys %$cookie_hash) {       # note the $

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      Thanks to all... Your help got on the right track to here: 
      my %hash = %{ $IN->{cookies} };

foreach my $k (keys %hash) {
  print "$hash{$k}[0]\n";
}

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Re: Dereferencing my hash?
by AnomalousMonk (Archbishop) on Feb 11, 2009 at 01:37 UTC
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