How to get this day last year in PHP?

Question

So I'm currently using Carbon for getting dates, times and comparisons. I can do subYear() easily enough to get this date last year. Now I need something to get the exact same day at the same time last year, e.g Wednesday of the second week of April.

I'd expect to have to do something that works out the current day of the week, e.g 3, and the current week of the year, then get the same value last year.

Just thought I'd check if there's anything available that already does this in Carbon or other PHP tools? Thanks

Answer 1

I think DateTime::setISODate() is exactly what you need:

$today = new \DateTime();

$year  = (int) $today->format('Y');
$week  = (int) $today->format('W'); // Week of the year
$day   = (int) $today->format('w'); // Day of the week (0 = sunday)

$sameDayLastYear = new \DateTime();
$sameDayLastYear->setISODate($year - 1, $week, $day);

echo "Today: ".$today->format('Y-m-d (l, W)').PHP_EOL;
echo "Same week and day last year: ".$sameDayLastYear->format('Y-m-d (l, W)').PHP_EOL;

Output (for today, 2015-05-05):

Today: 2015-05-05 (Tuesday, 19)
Same week and day last year: 2014-05-06 (Tuesday, 19)