$re = '/\w+\.(?=(com|uk))/m';
$str = '1) domain.com/our-work/insights/tips-and-advice/2008/02/04/the-path-to-good-design-is-proper-analytics
2) subdomain.domain.com
3) im.domain.com/About.htm
4) domain.uk/help.htm';
preg_match_all($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