col1,col2,col3,col4,col5,col6,col7,col8
1234,GP,20170715,0,V,97517,24,0.6
5678,Pack,20170715,0,V,97516,88,1.8
1234,GP,20170715,0,V,97517,22,0.6
5678,Pack,20170715,0,V,97517,183,3.9
1234,PRS,20170715,0,S,97517,261,5.4
5678,PRS,20170715,0,M,97517,36,0.9

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;

use Data::Table;

# Load input data from csv file
my $dt = Data::Table::fromCSV('data.csv');

# Make a new table that only contains the relevant columns
my $st = $dt->subTable(undef, [ 'col2', 'col7', 'col8' ]);
 
# Group by 'col2', calculate sums for 'col7' and 'col8'
my $ot = $st->group(
    ['col2'], # column to group by
    ['col7', 'col8'], # Columns to perform calculation on
    [ \&sum, \&sum ], # Apply sum function to 'col7' and 'col8'
    ['sum_of_col7', 'sum_of_col8'] # Put the sums in these columns 
);
print $ot->csv, "\n";

sub sum {
  my @data = @_;
  my $sum = 0;
  foreach my $x (@data) {
    next unless $x;
    $sum += $x;
  }
  return $sum;
}

exit;

##</code><code>##

col2,sum_of_col7,sum_of_col8
GP,46,1.2
Pack,271,5.7
PRS,297,6.3