Question

I need a regex for validating date and time with the following format: yyyy-mm-ddThh:mm:ss. T is just a symbol between date and time. Thanks for help

Answer 1

Fully-powered solution:

function validate($str) 
{
    preg_match('/^([0-9]{4})-([0-9]{2})-([0-9]{2})T([0-9]{2}):([0-9]{2}):([0-9]{2})$/', $str, $matches);

    if (count($matches) != 7)
        return false;

    $valid_year   = range(2000, 2050); // your range
    $valid_month  = range(1, 12);
    $valid_day    = range(1, 31);
    $valid_hour   = range(0, 24);
    $valid_minute = range(0, 59);
    $valid_second = range(0, 59);

    list($str, $year, $month, $day, $hour, $minute, $second) = $matches;

    foreach(array('year', 'month', 'day', 'hour', 'minute', 'second') as $part)
    {
        if (!in_array($$part, ${'valid_'.$part}))
            return false;
    }

    return checkdate($month, $day, $year); // this will reject absurd values like February 30 or April 31
}

EDIT: I don’t trust strtotime. For example: “The valid range of a timestamp is typically from Fri, 13 Dec 1901 20:45:54 UTC to Tue, 19 Jan 2038 03:14:07 UTC.” (quoted from strtotime manual page). What if I want to accept dates out of this range? To me, strtotime is an unknown black-box. Don’t get me wrong: I do use it, eventually! But I wouldn’t for this case.