$re = '/(^((\d{4}-(((0[13578]|[1][02])-(0[1-9]|[1-2]\d|3[01]))))|((\d{4}-(((0[469]|[1][1])-(0[1-9]|[1-2]\d|[3][0])))))|((\d{4}-(0[2]-(0[1-9]|[1-2]\d)))))T(([01]\d|2[0-3]):([0-5]\d):([0-5]\d))?([+-][0-2]\d:[0-5]\d)$)/m';
$str = '2022-02-29T22:58:00+05:30';
preg_match_all($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