$re = '/^[a-zA-Z]{3}[p|P|c|C|h|H|f|F|a|A|t|T|b|B|l|L|j|J|g|G][A-Za-z][\d]{4}[A-Za-z]$/m';
$str = 'dfxpk1218r';
preg_match_all($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