#!/usr/bin/env perl

use strict;
use warnings;

use Data::Dump;

my %hash;

while (<DATA>) {
    chomp;
    my ($value, $key) = split /\t/;
    push @{$hash{$key}}, $value;
} 

dd \%hash;

__DATA__
Obi Wan Jedi
Yoda    Jedi
Count Dooku Sith

##</code><code>##

{ Jedi => ["Obi Wan", "Yoda"], Sith => ["Count Dooku"] }

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;

use Text::CSV;
use Data::Dump;

my %hash;

my $csv = Text::CSV::->new({sep_char => "\t"});

while (my $row = $csv->getline(\*DATA)) {
    push @{$hash{$row->[1]}}, $row->[0];
}

dd \%hash;

__DATA__
Obi Wan Jedi
Yoda    Jedi
Count Dooku Sith

##</code><code>##

{ Jedi => ["Obi Wan", "Yoda"], Sith => ["Count Dooku"] }