DateTimeImmutable::add

(PHP 5 >= 5.5.0, PHP 7, PHP 8)

DateTimeImmutable::add — Returns a new object, with added amount of days, months, years, hours, minutes and seconds

说明

public DateTimeImmutable::add(DateInterval $interval): DateTimeImmutable

Adds the specified DateInterval object to the specified DateTime object, and returns a new DateTimeImmutable object to represent this new state.

参数

object: 仅过程化风格：由 date_create() 返回的 DateTime 类型的对象。此函数会修改这个对象。
interval: A DateInterval object

返回值

Returns a new modified DateTimeImmutable object 或者在失败时返回 false.

范例

示例 #1 DateTimeImmutable::add() example

面向对象风格


<?php
$date = new DateTimeImmutable('2000-01-01');
$newDate = $date->add(new DateInterval('P10D'));
echo $newDate->format('Y-m-d') . "\n";
?>

示例 #2 Further DateTimeImmutable::add() examples


<?php
$date = new DateTimeImmutable('2000-01-01');
$newDate = $date->add(new DateInterval('PT10H30S'));
echo $newDate->format('Y-m-d H:i:s') . "\n";

$date = new DateTimeImmutable('2000-01-01');
$newDate = $date->add(new DateInterval('P7Y5M4DT4H3M2S'));
echo $newDate->format('Y-m-d H:i:s') . "\n";
?>

以上例程会输出：

2000-01-01 10:00:30
2007-06-05 04:03:02

示例 #3 Beware when adding months


<?php
$date = new DateTimeImmutable('2000-12-31');
$interval = new DateInterval('P1M');

$newDate1 = $date->add($interval);
echo $newDate1->format('Y-m-d') . "\n";

$newDate2 = $newDate1->add($interval);
echo $newDate2->format('Y-m-d') . "\n";
?>

以上例程会输出：

2001-01-31
2001-03-03

参见

DateTimeImmutable::sub() - Subtracts an amount of days, months, years, hours, minutes and seconds
DateTimeImmutable::diff() - Returns the difference between two DateTime objects
DateTimeImmutable::modify() - Creates a new object with modified timestamp

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User Contributed Notes 1 note

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Gunnar Bernstein ¶

3 years ago


Please note, add() works a litte different than for DateTime-Objects.

Since DateTimeImmutable is in fact immutable. A line like this will not work:

    $di = new DateTimeImmutable("2018-12-12T10:00:00");
    $di->add(new DateInterval('PT45M')); // $di unchanged !!!

compared to

    $dt = new DateTime("2018-12-12T10:00:00");
    $dt->add(new DateInterval('PT45M')); // added 45 minutes

so you need to write

    $di = new DateTimeImmutable("2018-12-12T10:00:00");
    $di = $di->add(new DateInterval('PT45M')); // $di now changed

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