$re = '/\w+?\s\d{1,2},\s(\d{4})/m';
$str = '+-------------------------+
|Activity_date |
+-------------------------+
|Jul 20, 2015, 1:06:57 PM |
|Oct 11, 2015, 10:03:14 PM|
|Dec 8, 2016, 4:28:12 PM |
|Dec 12, 2016, 10:22:44 PM|
|Dec 25, 2016, 10:37:32 PM|
+-------------------------+';
preg_match_all($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