(PHP 5 >= 5.3.0, PHP 7)
DateTime::add -- date_add — Adds an amount of days, months, years, hours, minutes and seconds to a DateTime object
Object oriented style
public DateTime::add ( DateInterval $interval ) : DateTime
Procedural style
date_add ( DateTime $object , DateInterval $interval ) : DateTime
Adds the specified DateInterval object to the specified DateTime object.
object
Procedural style only: A DateTime object returned by date_create(). The function modifies this object.
interval A DateInterval object
Returns the DateTime object for method chaining or false on failure.
Example #1 DateTime::add() example
Object oriented style
<?php
$date = new DateTime('2000-01-01');
$date->add(new DateInterval('P10D'));
echo $date->format('Y-m-d') . "\n";
?> Procedural style
<?php
$date = date_create('2000-01-01');
date_add($date, date_interval_create_from_date_string('10 days'));
echo date_format($date, 'Y-m-d');
?> The above examples will output:
2000-01-11
Example #2 Further DateTime::add() examples
<?php
$date = new DateTime('2000-01-01');
$date->add(new DateInterval('PT10H30S'));
echo $date->format('Y-m-d H:i:s') . "\n";
$date = new DateTime('2000-01-01');
$date->add(new DateInterval('P7Y5M4DT4H3M2S'));
echo $date->format('Y-m-d H:i:s') . "\n";
?> The above example will output:
2000-01-01 10:00:30 2007-06-05 04:03:02
Example #3 Beware when adding months
<?php
$date = new DateTime('2000-12-31');
$interval = new DateInterval('P1M');
$date->add($interval);
echo $date->format('Y-m-d') . "\n";
$date->add($interval);
echo $date->format('Y-m-d') . "\n";
?> The above example will output:
2001-01-31 2001-03-03
DateTime::modify() is an alternative when using PHP 5.2.
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https://www.php.net/manual/en/datetime.add.php