$re = '/(?:\d+)(?:[\/.-](?:\d+)){1,2}/m';
$str = 'WC 12/10 change FC from 24 to 32
W/C 12/10 change fc from 401 to 340
W/C12/10 18 - 26
W?C 12/20/22 abc
';
preg_match_all($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