- var_dump: documentation ( source)
- floor: documentation ( source)
<?php
function datediffInWeeks($date1, $date2)
{
if($date1 > $date2) return datediffInWeeks($date2, $date1);
$first = DateTime::createFromFormat('m/d/Y', $date1);
$second = DateTime::createFromFormat('m/d/Y', $date2);
return floor($first->diff($second)->days/7);
}
$q = new DateTime('First Week of 2015');
var_dump($q);// 21