Just use a hash of arrays. 
use strict;
use warnings;

my %data;
while (<DATA>) {
    chomp;
    my ($k, $v) = split;
    push @{$data{$k}}, $v;
}

use Data::Dumper;
print Dumper(\%data);

__DATA__
1 A
1 B
2 B
4 X
5 V

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In reply to Re: Perl hashes: is there some way of adding more data to the value associated with an existing key? by wind
in thread Perl hashes: is there some way of adding more data to the value associated with an existing key? by mertserger

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