plus Week with PHP Date with GET? - php

Question

I have URL:
http://www.mysite.com/
here is:
$date = new DateTime("2011-11-28");
this show me:
2011-11-28
i would like add for this site buttons PREVIOUS and NEXT.
If i click NEXT then i have url:
http://www.mysite.com/number/2
now this show me:
2011-12-05 //(+ 7 days)
and i have buttons PREVIOUS (http://www.mysite.com/number/1) and NEXT (http://www.mysite.com/next/3)
etc.
How can i modify
$date = new DateTime("2011-11-28");
with $_GET['number'] ? i have modify from 2011-11-28 interval 7 day!

Answer 1

Check out DateTime::modify (available in PHP >= 5.2)
What you want to do is:
// just for checking if nobody is tampering with the number variable:
if (strcspn($_GET['number'], '0123456789') != strlen($_GET['number']) {
die('Invalid input!');
}
// actual calculation:
$amountOfDays = ((int)$_GET['number']) * 7;
$date = new DateTime("2011-11-28");
$date->modify('+'.$amountOfDays.' day');
Alternatively, you can use DateTime::add, but that is only defined in PHP versions >= 5.3.

Answer 2

Use add and sub to add/subtract days.
$date = new DateTime("2011-11-28");
$num = $_GET['number'];
$interval = new DateInterval('P'.$num.'W');
$date->add($interval);
Or, you can use modify
$date = new DateTime("2011-11-28");
$num = $_GET['number'];
$date->modify(($num>0 ? '+' : '').$num.' weeks');

Answer 3

You can also have a look at mktime()
http://php.net/manual/en/function.mktime.php
You can convert the primary date to a timestamp and add 7 days:
$new_date = mktime(0, 0, 0, 11, (28 + intval($_GET['number'])), 2011);
$visible_date = date('Y-m-d', $new_date);
echo $visible_date;

Answer 4

Use:
$date = new DateTime('#'.strtotime( $_GET['number'] . ' week'));
where $_GET['number'] is a natural number.

Answer 5

Try this:
$days = (intval($_GET['number']) - 1) * 7;
$date = new DateTime('2000-01-01');
$date->add(new DateInterval("P$daysD"));

Answer 6

I like strtotime a lot :)
It works like this:
$date = new DateTime("2011-11-28");
$prevWeek = strtotime('-1 week',$date);
$nextWeek = strtotime('+1 week',$date);