how to merge rows that share unique IDs into a comma separated table

Question

I would like to ask for some hints in how to merge rows that share unique IDs into a comma separated table. Any hints in Perl, sed or awk are greatly appreciated.

This i

Answer 1

Using a Perl hash of arrays...

#!/usr/bin/perl
use warnings;
use strict;

my %data;
my $header;

while(){
    chomp;

    if ($. == 1){
        $header = $_;
        next;
    }
    push @{ $data{(split)[0]} }, (split)[1];
}

print "$header\n";

for my $k (sort {$a<=>$b} keys %data){

    print "$k\t";
    print join(', ', @{ $data{$k} });
    print "\n";
}

__DATA__
protein_id go_id
4102    GO:0003676
4125    GO:0003676
4125    GO:0008270
4139    GO:0008270