How to loop through weeks in different year - php

Question

I have input as $fromweek=50 and $fromyear=2015
then $toweek=2 and $toyear=2016
How do I loop week number in a table column ?
for ($i=$fromweek; $i<=$toweek; $i++) {
echo '<th>week '.$i.'</th>';
}

Answer 1

You need to be careful here as according to the ISO 8601 standard some years can have 53 weeks. Your example year, 2015 is one of these.
The \DateTime classes are the way to do this. They will automatically account for leapyears etc and make date manipulation much easier. It is worth taking the time to read up on them.
Something like this should work for you:
$fromweek=50;
$fromyear=2015;
$toweek=2;
$toyear=2016;
$interval = new DateInterval('P7D');
$start = (new \DateTime())->setISODate($fromyear, $fromweek);
$end = (new \DateTime())->setISODate($toyear, $toweek);
$period = new \DatePeriod($start, $interval, $end->add($interval));
foreach($period as $date){
echo $date->format('d-m-Y') . PHP_EOL;
}
See it working.

Answer 2

You could create two dates using week number and year, and compare them (while $date1 exceeds $date2), and increase $date1 by week using DateInterval, see example below:
$date1 = new DateTime();
$date1->setISODate(2015, 50);
$date2 = new DateTime();
$date2->setISODate(2016, 2);
while($date1 <= $date2) {
echo $date1->format('W').PHP_EOL;
$date1->add(new DateInterval('P1W'));
}
In Action: https://eval.in/573305