use warnings;
use strict;
use Data::Dumper;

my @CELLS=( 'A-1', 'A-2', 'A-3', 'A-4', 'B-5', 'B-6', 'C-7', 'C-8');

my %hash=map { /^(.*)-(\d+)$/; $1=>$2} @CELLS;

print STDERR "hash DUMPER:\n", Dumper(\%hash), "\n";

##</code><code>##

hash DUMPER:
$VAR1 = {
          'A' => '4',
          'C' => '8',
          'B' => '6'
        };

##</code><code>##

hash DUMPER:
$VAR1 = {
          'A' => [
                   1,
                   2,
                   3,
                   4
                 ],
          'C' => [
                   7,
                   8
                 ],
          'B' => [
                   5,
                   6
                 ]
        };