PHP check if two Datetimes are not on the same calendar day

Question

I have two Datetimes like this (the dates being actually $vars)

$startTime = \\DateTime::createFromFormat(\'Y/m/d H:i\', \'2015/01/01 23:00\');
$endTime = \\Date         


        

Answer 1

Just create the dates with time set to 00:00:00:

$startTime = \DateTime::createFromFormat('Y/m/d H:i:s', '2015/01/01 00:00:00');
$endTime = \DateTime::createFromFormat('Y/m/d H:i:s', '2015/01/02 00:00:00');

or reset time to zero on existing dates:

$startTime->setTime(0, 0, 0);
$endTime->setTime(0, 0, 0);

then it should work:

$diff = $startTime->diff($endTime);
$days = $diff->format('%d');

echo $days; // 1

Bonus

If you want to work only with dates, remember to set the time to 00:00:00 in createFromFormat or reset it with setTime. If you won't provide time in createFromFormat PHP will set it to the current time:

$date = DateTime::createFromFormat('Y-m-d', '2016-01-21');
print $date->format('H:i:s'); //not 00:00:00

To fix it, you must either:

• provide 00:00:00 time in format:

  $date = DateTime::createFromFormat('Y-m-d H:i:s', '2016-01-21 00:00:00');

• prefix the date format with exclamation mark and omit the time, this will set the time to 00:00:00 automatically:

  $date = DateTime::createFromFormat('!Y-m-d', '2016-01-21');

• reset the time after creation:

  $date = DateTime::createFromFormat('Y-m-d', '2016-01-21'); $date->setTime(0, 0);

Answer 2

I think this is one of the few situations where the use of strings for date calculations is justified:

function onDifferentDays(\DateTimeInterface $startTime, \DateTimeInterface $endTime){
    return $startTime->format('Y-m-d')!==$endTime->format('Y-m-d');
}

This code should be easy to extend to include time zone.

There're other alternatives but I don't think they're normally worth the effort:

1. Compare element by element (day, month and year):

   • The PHP DateTime class doesn't offer dedicated functions, only format().

2. Normalize both dates to a common time and compare with == (not ===):

   • Unless you're using immutable objects you need to clone input or expect side effects

   • You also need to ensure that time exists in the active time zone though midnight is probably safe enough.

Whatever, YMMV ;-)

Answer 3

Comparing formatted dates is the right thing to do:

$a->format('Y-m-d') === $b->format('Y-m-d')

There is a method for that if you use Carbon:

$dt1->isSameDay($dt2)

So I recommend to use it instead of previous answers given here.

http://carbondoc/docs/#api-comparison