my $string = "1-2, 3-4, 5-6";


#strip anything but the last digit,
$string =~ s/^.*(\d)$/$1/;
# string now holds only the last digit, rest should be removed

##</code><code>##

my $last_digit = '';
if ($string =~ /(\d)$/) {
    $last_digit = $1;
}

##</code><code>##

my $last_digit = '';
if ($string =~ /(\d){1}$/) {
    $last_digit = $1;
}