$re = '/(string1.+?)(?:\'string2)/';
$str = '[\'string1\',\'string2\',\'string3\']
[\'string1\' , \'string2\' , \'string3\']
[\'string1.domain.com\' , \'string2.domain.com\' , \'string3.domain.com\']
[\'string1.domain.com:8080\' , \'string2.domain.com:8080\' , \'string3.domain.com:8080\']';
preg_match_all($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