Validate that input is in this time format - "HH:MM" [closed]

Question

I'm trying to use preg_match to validate that a time input is in this format - "HH:MM"

Answer 1

You can use regular expressions to check that.

for 12-hour:

preg_match("/^(?:1[012]|0[0-9]):[0-5][0-9]$/", $foo)

for 24-hour:

preg_match("/^(?:2[0-3]|[01][0-9]):[0-5][0-9]$/", $foo)

If you use a 24-hour clock going from 01:00 to 24:59, use

preg_match("/^(?:2[0-4]|[01][1-9]|10):([0-5][0-9])$/", $foo)

Answer 2

Simple function that validates a date (and/or time) without throwing exceptions. It takes the expected date format as a parameter:

function isValidDate(string $date, string $format = 'Y-m-d'): bool
{
    $dateObj = DateTime::createFromFormat($format, $date);
    return $dateObj && $dateObj->format($format) == $date;
}

How it works: it converts the input date into a PHP DateTime object according to the passed $format, then compares this object with the original input date. If they match, the date is valid and has the expected format.

Some usage examples:

/* Valid Examples: */
isValidDate("2017-05-31");
isValidDate("23:15:00", 'H:i:s');
isValidDate("2017-05-31 11:15:00", 'Y-m-d h:i:s');

/* Invalid: */
isValidDate("2012-00-21");
isValidDate("25:15:00", 'H:i:s');
isValidDate("Any string that's not a valid date/time");

Answer 3

Let's imagine the time you want to check is $timeStr and has to be the format H:i according to the date specs. Using a regex for this is IMHO silly. This is so much easier to read:

UPDATED

$timeStr = " 02:00"; //example of valid time, note whitespace
test($timeStr);
$timeStr = "23:59"; //valid
test($timeStr);
$timeStr = "24:00"; //invalid
test($timeStr);
$timeStr = "25:00"; //invalid
test($timeStr);    
$timeStr = "16:61"; // invalid
test($timeStr);

//tests 23:59 hour format
    function test($timeStr){

    $dateObj = DateTime::createFromFormat('d.m.Y H:i', "10.10.2010 " . $timeStr);

    if ($dateObj !== false && $dateObj && $dateObj->format('G') == 
        intval($timeStr)){
        //return true;
        echo 'valid  <br/>';
    }
    else{
      //return false;
      echo 'invalid <br/>';
    }

}