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

Hi everyone.
My input data are like the following:

$VAR1 = { 'dove-n' => { 'mero' => { 'rump-n' => '0.0986331918077933', 'plume-n' => '0.164895598193776', 'beak-n' => '0.148781820621755', 'head-n' => '0.541972342596793', }, 'random-v' => { 'pile-v' => '0.006058551416765 +5', 'kiss-v' => '0.005277682171536 +47', }, 'cockroach-n' => { 'mero' => { 'exoskeleton-n' => '0.0665736 +517016939', 'leg-n' => '0.440277128001941 +', }, 'random-v' => { 'suggest-v' => '0.0148588 +863336517', 'guarantee-v' => '0.00591 +007188858908', 'land-v' => '0.0149882471 +117093', },

For each keys, I need the entries to be sorted by their score, so for example I'll have something like:

dove-n mero head-n 0.541972342596793 dove-n mero beak-n 0.148781820621755 dove-n mero plume-n 0.164895598193776 dove-n mero rump-n 0.0986331918077933 dove-n random-v pile-v 0.0060585514167655 dove-n random-v kiss-v 0.00527768217153647 cockroach-n mero leg-n 0.440277128001941 cockroach-n random-v suggest-v 0.0665736517016939 cockroach-n mero exoskeleton-n 0.0148588863336517 cockroach-n random-v land-v 0.0149882471117093 cockroach-n random-v guarantee-v 0.00591007188858908

I've tried reading this: http://perldoc.perl.org/perlfaq4.html#How-do-I-sort-an-array-by-%28anything%29? but I really don't get how I can achieve what I need. Any suggestions?
Thanks,
Giulia

Replies are listed 'Best First'.
Re: Sorting Hashes of hashes
by kcott (Archbishop) on Mar 06, 2012 at 16:28 UTC

    Your input data ($VAR1) is an invalid hashref and your example output is not sorted.

    After fixing the input and guessing you want highest score first, this code:

    #!/usr/bin/env perl use strict; use warnings; my $data = { 'dove-n' => { 'mero' => { 'rump-n' => '0.0986331918077933', 'plume-n' => '0.164895598193776', 'beak-n' => '0.148781820621755', 'head-n' => '0.541972342596793', }, 'random-v' => { 'pile-v' => '0.0060585514167655', 'kiss-v' => '0.00527768217153647', }, }, 'cockroach-n' => { 'mero' => { 'exoskeleton-n' => '0.0665736517016939', 'leg-n' => '0.440277128001941', }, 'random-v' => { 'suggest-v' => '0.0148588863336517', 'guarantee-v' => '0.00591007188858908', 'land-v' => '0.0149882471117093', }, }, }; for my $animal (keys %$data) { my @record = (); for my $type (keys %{$data->{$animal}}) { for my $part (keys %{$data->{$animal}{$type}}) { push @record, [$animal, $type, $part, $data->{$animal}{$ty +pe}{$part}]; } } map { print join(q{ } => @$_), qq{\n} } sort { $b->[3] <=> $a->[3] + } @record; }

    produces this output:

    dove-n mero head-n 0.541972342596793 dove-n mero plume-n 0.164895598193776 dove-n mero beak-n 0.148781820621755 dove-n mero rump-n 0.0986331918077933 dove-n random-v pile-v 0.0060585514167655 dove-n random-v kiss-v 0.00527768217153647 cockroach-n mero leg-n 0.440277128001941 cockroach-n mero exoskeleton-n 0.0665736517016939 cockroach-n random-v land-v 0.0149882471117093 cockroach-n random-v suggest-v 0.0148588863336517 cockroach-n random-v guarantee-v 0.00591007188858908

    The technique I've used here is to flatten the hash data into individual records and then sort those records.

    To reverse the sort order (lowest score first), just swap $a and $b, i.e.

    ... sort { $a->[3] <=> $b->[3] } ...

    -- Ken

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