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

Helo monks, How do I sort this HoH based on the 'score'? 
my $HoH = {
          'pk1' => {
                      'sk1'  => 'val1',
                      'sk2'  => 'val2,
                      'score'=> 47
                         },

          'pk2' => {
                      'sk1' => 'val3',
                      'sk2' => 'val4',
                      'score' => 14
                         },
          'pk3' => {
                      'sk1' => 'val5',
                      'sk2' => 'val6',
                      'score' => 64
                    }
        };

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I have this snippet that try to get the sorted keys. 
my @best_key = sort { keys %{$HoH{'score'}{$a}} <=> keys %{$HoH{'score
+'}{$b}}  } keys %HoH;

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Supposedly it returns: pk3,pk1,pk2 as result. But it fails. Many thanks for your time.

Replies are listed 'Best First'.
Re: Sorting HoH
by Hena (Friar) on May 25, 2005 at 07:29 UTC
    This kind of questions tend to have answers in Q&A. I would suggest reading node 320255.
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Re: Sorting HoH
by holli (Abbot) on May 25, 2005 at 07:33 UTC
    You cannot sort a hash. All you can get is a list of sorted keys: 
    my $HoH = 
{
    'pk1' => 
    {
        'sk1'   => 'val1',
        'sk2'   => 'val2',
        'score' => 47,
    },

    'pk2' => 
    {
        'sk1'   => 'val3',
        'sk2'   => 'val4',
        'score' => 14
    },

    'pk3' => 
    {
        'sk1'   => 'val5',
        'sk2'   => 'val6',
        'score' => 64
    }
};
        
my @keys = sort { $HoH->{$a}->{score} <=> $HoH->{$b}->{score} } keys %
+{$HoH};
print "@keys";

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    holli, /regexed monk/
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[d/l]
      You cannot sort a hash

      I dunno...  sort %hash seems to work for me :)
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[d/l]
Re: Sorting HoH
by Fang (Pilgrim) on May 25, 2005 at 07:34 UTC

    my @best_keys = sort { $HoH->{$a}{'score'} <=> $HoH->{$b}{'score'} } keys %{$HoH}

    The $a and $b special variables are taken from keys %{$HoH}, so that's where they should be in the sort sub. Reread perldoc -f sort.

    Note you're missing a closing ' in your code, too ('sk2' => 'val2,).

    Update: just noticed you wanted the keys in descending order of their score value, just swap $a and $b in the code.

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[d/l]
Re: Sorting HoH
by thcsoft (Monk) on May 25, 2005 at 08:48 UTC 
    perldoc perldata
perldoc -f sort

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    language is a virus from outer space.
[reply]
[d/l]

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