$re = '/^[a-zA-Z0-9]{3,8}-\d{1}$/m';
$str = '# Genuine values
63638-1
8867-4
55231-5
26464-8
22577-1
# Checking edge cases
12-1
123-1
12345678-9
123456789-9
12345678
12345678-
12345678--
12345678-A
12345678-?
12345678-12
# Adding letters to the main code
LL2435-7
LL358-3
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php