use strict;
use warnings;

use Data::Dumper;

my @results;
while (<DATA>) {
        my @row = split;
        for (my $idx = 0; $idx < 3; $idx++) {
                push @{ $results[$idx] }, $row[$idx];
        }
}

# Assume @results already populated...
my ($day_of_week, $production_line, $output) = @results;
my @data_to_plot;

# Ignore the headers
for (my $idx = 0; $idx < 3; $idx++) { shift @{ $results[$idx] } }

###
# Extending an idea from [http://www.perl.com/doc/FAQs/FAQ/oldfaq-html/Q5.4.html]...
my %saw;
my %production_lines = ( map { $_ => [] } grep ! $saw{$_}++, @$production_line );
#
###

for (my $index = 0; $index < @$day_of_week; $index++) {
    push @{ $data_to_plot[0] }, $day_of_week->[$index] unless
        grep /^$day_of_week->[$index]$/, @{ $data_to_plot[0] };

    push @{ $production_lines{$production_line->[$index]} }, $output->[$index];
}

push @data_to_plot, ( map { $production_lines{$_} } sort keys %production_lines );

print Dumper \@data_to_plot;

__DATA__
DayOfWeek       ProductionLine  Output
2       CANNING 18353
2       MULTIPACK       14878
2       QUEST   911
3       CANNING 46775
3       MULTIPACK       42601
3       QUEST   1564
4       CANNING 81302
4       MULTIPACK       67542
4       QUEST   1879

.
.