DateTime::modify

(PHP 5 >= 5.2.0)

DateTime::modify — Alters the timestamp

Description

Object oriented style

public DateTime DateTime::modify ( string $modify )

Procedural style

DateTime date_modify ( DateTime $object , string $modify )

Alter the timestamp of a DateTime object by incrementing or decrementing in a format accepted by strtotime().

Parameters

object

Procedural style only: A DateTime object returned by date_create(). The function modifies this object.

modify

A date/time string. Valid formats are explained in Date and Time Formats.

Return Values

Returns the modified DateTime object or FALSE on failure.

Changelog

Version	Description
5.3.0	Changed the return value on success from NULL to DateTime.

Examples

Example #1 DateTime::modify() example

Object oriented style

<?php
$date = new DateTime('2006-12-12');
$date->modify('+1 day');
echo $date->format('Y-m-d');
?>

Procedural style

<?php
$date = date_create('2006-12-12');
date_modify($date, '+1 day');
echo date_format($date, 'Y-m-d');
?>

The above examples will output:

2006-12-13

Example #2 Beware when adding or subtracting months

<?php
$date = new DateTime('2000-12-31');

$date->modify('+1 month');
echo $date->format('Y-m-d') . "\n";

$date->modify('+1 month');
echo $date->format('Y-m-d') . "\n";
?>

The above example will output:

2001-01-31
2001-03-03

See Also

• strtotime() - Parse about any English textual datetime description into a Unix timestamp
• DateTime::add() - Adds an amount of days, months, years, hours, minutes and seconds to a DateTime object
• DateTime::sub() - Subtracts an amount of days, months, years, hours, minutes and seconds from a DateTime object
• DateTime::setDate() - Sets the date
• DateTime::setISODate() - Sets the ISO date
• DateTime::setTime() - Sets the time
• DateTime::setTimestamp() - Sets the date and time based on an Unix timestamp