$re = '/(.*)\s(?:s?|se)(\d+)\s?(?:e|x|ep)\s?(\d+)/m';
$str = 'Da Vinci\'s Demons se02ep04 whatsoever
Da Vinci\'s Demons se02 ep04
Da Vinci\'s Demons s02e123
Da Vinci\'s Demons s02 e04
Da Vinci\'s Demons 02x04
Da Vinci\'s Demons 02 x04
Da Vinci\'s Demons 02 x 04
';
preg_match_all($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