Add a year or a month to a date.

QuickFix

Hey,

I use the following code to add a year to the current date:

$new_date = date('Y-m-d',strtotime('+1 year'));

But I'm not sure how to add a year to a date which is not today, for example '2006-12-31' which is contained in a string $old_date.

I also need to figure out how to add a month to $old_date.

I'd appreciate any help. I've been googling for hours, but I can only find methods for adding a year to the current date which is easy.

Thanks
QuickFix

PHPist

Try to use timestamps, it's are more usefull then strtotime();
To create timestamp() you can use function int
int mktime ( [int hour [, int minute [, int second [, int month [, int day [, int year [, int is_dst]]]]]]] )
For example:
<?
//Date string
$date='13-01-2005';
//Get day,mount,year use parsing by '-'
$data=explode("-",$date);
//Create stamp, with old day and mounth and today year
$stamp=mktime(0,0,0,$date[1],$date[0],date("Y"));
//And after that you can format date by this data
$date=date('d-m-Y',$stamp);
print $date;
?>
If it not what you looking for, told.

bradgrafelman

Simple - [man]strtotime/man can do addition and subtraction:

$old_date = '2006-12-31';
$new_date = strtotime($old_date . ' +1 year');
$prev_month = strtotime($old_date . ' -1 month');

EDIT: On second glance, it appears that strtotime() may not behave as you expect it to all the time. For example, using the -1 month from the old_date gave me a date of 2006-12-01.

1 month prior to 2006-12-30, however, reported 2006-11-30.

Installer

Try to use timestamps, it's are more usefull then strtotime();

??
strtotime() is a timestamp.

Weedpacket

bradgrafelman wrote:
On second glance, it appears that strtotime() may not behave as you expect it to all the time..

Yup; it's something to watch out for: "date -1 month" means "the same date less one month": 2006-12-31 less one month is 2006-11-31; which by all conventions is the day after 2006-11-30. Are we in fact talking about "the last day of the month" here?