$re = '/^(?!.*pet).*/m';
$str = '"/pet",
"/pet/findByStatus",
"/pet/findByTags",
"/pet/{petId}",
"/pet/{petId}/uploadImage",
"/store/inventory",
"/store/order",
"/store/order/{orderId}",
"/user",
"/user/createWithArray",
"/user/createWithList",
"/user/login",
"/user/logout",
"/user/{username}"';
preg_match_all($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