DateTimeInterface::diff
DateTimeImmutable::diff
DateTime::diff
date_diff
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
DateTimeInterface::diff -- DateTimeImmutable::diff -- DateTime::diff -- date_diff — Returns the difference between two DateTime objects
Description
Object-oriented style
Parameters
datetime-
The date to compare to.
absolute-
Should the interval be forced to be positive?
Return Values
The DateInterval object represents the
difference between the two dates.
The absolute parameter only affects the
invert property of a
DateInterval object.
The return value more specifically represents the clock-time interval to
apply to the original object ($this or
$originObject) to arrive at the
$targetObject. This process is not always
reversible.
The method is aware of DST changeovers, and hence can return an interval of
24 hours and 30 minutes, as per one of the examples. If
you want to calculate with absolute time, you need to convert both the
$this/$baseObject, and
$targetObject to UTC first.
Examples
Example #1 DateTimeImmutable::diff() example
<?php
$origin = new DateTimeImmutable('2009-10-11');
$target = new DateTimeImmutable('2009-10-13');
$interval = $origin->diff($target);
echo $interval->format('%R%a days');
The above example will output:
<?php
$origin = date_create('2009-10-11');
$target = date_create('2009-10-13');
$interval = date_diff($origin, $target);
echo $interval->format('%R%a days');
The above example will output:
Example #2 DateTimeInterface::diff() during DST
changeover
<?php
$originalTime = new DateTimeImmutable("2021-10-30 09:00:00 Europe/London");
$targetTime = new DateTimeImmutable("2021-10-31 08:30:00 Europe/London");
$interval = $originalTime->diff($targetTime);
echo $interval->format("%H:%I:%S (Full days: %a)"), "\n";
The above example will output:
Example #3 DateTimeInterface::diff() range
The value that the method returns is the exact amount of time to get from
$this to $targetObject.
Comparing January 1st to December 31st returns therefore 364, and not 365,
days (for non-leap years).
<?php
$originalTime = new DateTimeImmutable("2023-01-01 UTC");
$targetTime = new DateTimeImmutable("2023-12-31 UTC");
$interval = $originalTime->diff($targetTime);
echo "Full days: ", $interval->format("%a"), "\n";
The above example will output:
Example #4 DateTime object comparison
Note:
DateTimeImmutable and
DateTime objects can be compared using
comparison operators.
<?php
$date1 = new DateTime("now");
$date2 = new DateTime("tomorrow");
var_dump($date1 == $date2);
var_dump($date1 < $date2);
var_dump($date1 > $date2);
The above example will output:
bool(false)
bool(true)
bool(false)
See Also
- DateInterval::format() - Formats the interval
- DateTime::add() - Modifies a DateTime object, with added amount of days, months, years, hours, minutes and seconds
- DateTime::sub() - Subtracts an amount of days, months, years, hours, minutes and seconds from
a DateTime object
DateTimeInterface
DateTimeInterface