$re = '/^(\'[0-9]*\',?){3}$/m';
$str = ' Account Source Source2 Source3 Source4 Source5
\'39\',\'39\'
\'41\',\'41\'
\'67\',\'67\'
\'286\',\'286\'
\'\',\'299\',\'2312210299\'
\'307\',\'307\'
\'341\',\'341\'
\'349\',\'349\'
\'351\',\'351\'
\'359\',\'359\'
\'362\',\'362\'
\'363\',\'363\'
\'378\',\'378\'
\'511\',\'511\',\'6218\',\'2197360511\'';
preg_match_all($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