use strict;
use Data::Dumper; # for investigating data structures

my %data;   # load data into hash of arrays
while (<DATA>)
{
    chomp;
    my @fields = split/,/;
    $data{$fields[0]} = \@fields; # first column = hash key
}
print "\%data - \n", Dumper(\%data);

# We will transform the hash into a sorted array
# sorted on the 3rd column (score)
my @array = sort { $a->[2] <=> $b->[2] } map { $data{$_} } keys %data;
print "\@array - \n", Dumper(\@array);

# Output sorted data lines
print "Sorted data - \n";
foreach (@array)
{
	printf "%s\n", join ',', @{$_};
}

__DATA__
Sequence1,0001,80
Sequence2,0002,20
Sequence3,0003,40
Sequence4,0004,100
Sequence5,0005,70

##</code><code>##

%data -
$VAR1 = {
          'Sequence1' => [
                           'Sequence1',
                           '0001',
                           '80'
                         ],
          'Sequence2' => [
                           'Sequence2',
                           '0002',
                           '20'
                         ],
          'Sequence3' => [
                           'Sequence3',
                           '0003',
                           '40'
                         ],
          'Sequence4' => [
                           'Sequence4',
                           '0004',
                           '100'
                         ],
          'Sequence5' => [
                           'Sequence5',
                           '0005',
                           '70'
                         ]
        };

@array -
$VAR1 = [
          [
            'Sequence2',
            '0002',
            '20'
          ],
          [
            'Sequence3',
            '0003',
            '40'
          ],
          [
            'Sequence5',
            '0005',
            '70'
          ],
          [
            'Sequence1',
            '0001',
            '80'
          ],
          [
            'Sequence4',
            '0004',
            '100'
          ]
        ];

Sorted data -
Sequence2,0002,20
Sequence3,0003,40
Sequence5,0005,70
Sequence1,0001,80
Sequence4,0004,100

##</code><code>##

my %data;
$data{key} = value;

##</code><code>##

%data->{key} = value;

##</code><code>##

@sorted_array =
  map {$_->[0] }
  sort { $a->[1] <=> $b->[1] }
  map { [ $_, (split/,/)[2] ] } # retrieve the third key
  @original_array;