Online PHP editor | output for 1jg0d

<?php $dates=[ '2017-02-28', // group1 '2017-03-01', // group1 '2017-04-03', // group2 '2017-04-04', // group2 '2017-04-06', // group3 '2017-04-08', // group4 '2017-04-09', // group4 '2017-04-10' // group4 ]; foreach($dates as $date){ if(!isset($start_date)){ $start_date=$date; // temporarily store new start date }elseif($date==date("Y-m-d",strtotime("$start_date +1 day")) || (isset($end_date) && $date==date("Y-m-d",strtotime("$end_date +1 day")))){ $end_date=$date; // temporarily store new or overwrite existing end date }else{ $result[]="$start_date to ".(!isset($end_date)?$start_date:$end_date); // current date is not in group, move temporary dates to result array $start_date=$date; // overwrite previous start date unset($end_date); // destroy previous end date } } $result[]="$start_date to ".(!isset($end_date)?$start_date:$end_date); // move temporary dates to result array var_export($result);