Online PHP editor | output for uV9Ft

<?php $firstAvailableCount = 100; $slice = 'weekly'; $countData = array(); $startDateTime = new DateTime("2016-01-10"); $endDateTime = new DateTime("2016-01-12"); fillCountMapPeriod($startDateTime,$endDateTime,$countData,$firstAvailableCount,$slice); function fillCountMapPeriod( DateTime $startDateTime, DateTime $endDateTime, array $countData, $firstAvailableCount, $slice) { if($slice == 'monthly') { $interval = new DateInterval('P1M'); $format = 'm-Y'; $startDateTime = DateTime::createFromFormat($format."-d",$startDateTime->format($format).-"1"); $endDateTime = DateTime::createFromFormat($format."-d",$endDateTime->format($format).-"1"); } else { $interval = new DateInterval('P1W'); $format = 'W-Y'; } if($startDateTime->format($format) == $endDateTime->format($format)) { var_dump($startDateTime->format($format)); return; } //var_dump($endDateTime); while($startDateTime <= $endDateTime){ var_dump($startDateTime->format("d-".$format)); $startDateTime->add($interval); } }