PHP Manual
DateTimeInterface
Returns the difference between two DateTime objects

DateTime::diff

DateTimeImmutable::diff

DateTimeInterface::diff

date_diff

(PHP 5 >= 5.3.0, PHP 7)

DateTime::diff -- DateTimeImmutable::diff -- DateTimeInterface::diff -- date_diff — Returns the difference between two DateTime objects

说明

面向对象风格

public DateTime::diff ( DateTimeInterface $datetime2 [, bool $absolute = FALSE ] ) : DateInterval

public DateTimeImmutable::diff ( DateTimeInterface $datetime2 [, bool $absolute = FALSE ] ) : DateInterval

public DateTimeInterface::diff ( DateTimeInterface $datetime2 [, bool $absolute = FALSE ] ) : DateInterval

过程化风格

date_diff ( DateTimeInterface $datetime1 , DateTimeInterface $datetime2 [, bool $absolute = FALSE ] ) : DateInterval

Returns the difference between two DateTimeInterface objects.

参数

datetime: The date to compare to.
absolute: Should the interval be forced to be positive?

返回值

The DateInterval object representing the difference between the two dates 或者在失败时返回 FALSE.

范例

Example #1 DateTime::diff() example

面向对象风格

 <?php
$datetime1 = new DateTime('2009-10-11');
$datetime2 = new DateTime('2009-10-13');
$interval = $datetime1->diff($datetime2);
echo $interval->format('%R%a days');
?>

过程化风格

 <?php
$datetime1 = date_create('2009-10-11');
$datetime2 = date_create('2009-10-13');
$interval = date_diff($datetime1, $datetime2);
echo $interval->format('%R%a days');
?>

以上例程会输出：

+2 days

Example #2 DateTime object comparison

Note:

As of PHP 5.2.2, 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);
?>

以上例程会输出：

bool(false)
bool(true)
bool(false)

参见

DateInterval::format() - Formats the interval
DateTime::add() - 给一个 DateTime 对象增加一定量的天，月，年，小时，分钟以及秒。
DateTime::sub() - 对一个 DateTime 对象减去一定量的日、月、年、小时、分钟和秒。