DateTime
As noted in DateTime::modify comment The P6M sometimes gives nonintuitive results, especially for last day of the month: 2009-05-31 + 1 month = 2009-06-31 => 2009-07-01;
To get expected behavior convert the date to first day of month , modify date, than use 't' for day in format to get last day of the month.
Example:
<?php
$f = 'Y-m-d H:i:s';
$f1 = 'Y-m-01 H:i:s';
$fL = 'Y-m-t H:i:s';
//EXPECTED
$lastDayOfTheMonth = new DateTime('2009-12-31 00:00:00');
$firstDayOfTheMonth = new DateTime($lastDayOfTheMonth->format($f1));
//echoes 2009-06-30
echo $lastDayNext6Months = $firstDayOfTheMonth->add(new DateInterval("P6M"))->format($fL),'<br />';
//NON-EXPECTED
$lastDayOfTheMonth = new DateTime('2009-12-31 00:00:00');
//echoes 2009-07-01
echo $lastDayNext6Months = $lastDayOfTheMonth->add(new DateInterval("P6M"))->format($f),'<br />';
?>
DateTime::add
(PHP 5 >= 5.3.0)
DateTime::add — Adds an amount of days, months, years, hours, minutes and seconds to a DateTime object
Description
Adds the specified DateInterval object to the specified DateTime object.
Parameters
- object
-
Procedural style only: A DateTime object returned by date_create()
- interval
-
A DateInterval object
Return Values
Returns the modified DateTime.
Examples
Example #1 date_add() example
<?php
$date = new DateTime("18-July-2008 16:30:30");
echo $date->format("d-m-Y H:i:s").'<br />';
date_add($date, new DateInterval("P5D"));
echo '<br />'.$date->format("d-m-Y").' : 5 Days';
date_add($date, new DateInterval("P5M"));
echo '<br />'.$date->format("d-m-Y").' : 5 Months';
date_add($date, new DateInterval("P5Y"));
echo '<br />'.$date->format("d-m-Y").' : 5 Years';
date_add($date, new DateInterval("P5Y5M5D"));
echo '<br />'.$date->format("d-m-Y").' : 5 Days, 5 Months, 5 Years';
date_add($date, new DateInterval("P5YT5H"));
echo '<br />'.$date->format("d-m-Y H:i:s").' : 5 Years, 5 Hours';
?>
See Also
- DateTime::sub() - Subtracts an amount of days, months, years, hours, minutes and seconds from a DateTime object
- DateTime::diff() - Returns the difference between two DateTime objects
add a note
User Contributed NotesDateTime::add
kb at imodus dot pl
07-Dec-2009 09:56
07-Dec-2009 09:56
antonchanning at gmail dot com
23-Sep-2009 12:32
23-Sep-2009 12:32
If you are currently using php 5.2.x (The latest version in the Ubuntu repository is 5.2.4 as I write this), and need to add to a date, consider whether using DateTime::modify will work for you, as DateTime::add is only available from 5.3