#!/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'
                 ]
        };