Recycling my answer from here

To build a hashe of arrays , you need to store, arrayrefs in the hash, like this

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

my %foo;
my @bar;
$foo{bar}=\@bar;
$foo{BAR}=\@bar;
for ( 1 .. 2){
    my @arr = "ab$_" .. "ab4";
    $foo{$_} = \@arr;
}

use Data::Dumper;
print Dumper( \%foo );
__END__
$VAR1 = {
          '1' => [
                   'ab1',
                   'ab2',
                   'ab3',
                   'ab4'
                 ],
          'bar' => [],
          'BAR' => $VAR1->{'bar'},
          '2' => [
                   'ab2',
                   'ab3',
                   'ab4'
                 ]
        };
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See the \ operator takes a reference, to an array (\@array), to a hash (\%hash), to a scalar (\$scalar)

See Tutorials: References quick reference