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

I have the following code: 
use Data::Dumper;
while (<DATA>){
next if /^$/;
($f,$s) = split /\|/,$_;
$h{$f} += $f;
$h->{$f}{'s'} += $s;
}

for my $k (sort {$h{$b} <=> $h{$a} } keys %h){
print "Key = $k\nElement 1: $h{$k}\nElement 3: $h->{$k}{'s'}\n";
};

#print Dumper{%{$h}};
__DATA__
1|2
2|4
2|4
4|3
4|5
5|1
5|2

[download]
I want to sort by $h->{$f}{'s'} so that the total of the third element is sorted as: 8 8 3 2 rather than by element two: 10 8 4 1. How can I achieve this? Thanks.

Replies are listed 'Best First'.
Re: Sorting a Hash of Hashes by Value
by ikegami (Patriarch) on Oct 29, 2007 at 13:46 UTC

    Short answer: 

    sort { $h->{$b}{s} <=> $h->{$a}{s} } keys %$h

    [download]

    Do you realize you have two identically-keyed hashes (%h and %$h)? Let's merge the two. 

    use strict;
use warnings;

my %totals;
while (<DATA>){
   next if /^$/;
   my ($f,$s) = split /\|/,$_;
   $totals{$f}{f} += $f;
   $totals{$f}{s} += $s;
}

for my $k (sort { $totals{$b}{s} <=> $totals{$a}{s} } keys %totals) {
   print "Key = $k\n"
   print "Element 1: $total{$k}{f}\n";
   print "Element 3: $total{$k}{s}\n";
}

    [download]
[reply]
[d/l]
[select]
      I like this approach better of having all total counts merged into one single hash. Thanks for the guidance. Much appreciated.
[reply]
Re: Sorting a Hash of Hashes by Value
by Anonymous Monk on Oct 29, 2007 at 13:45 UTC
    ?! 
    sort { $h->{$b}{'s'} <=> $h->{$a}{'s'} }

    [download]
[reply]
[d/l]

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