Online PHP editor | refs for oRNVH

<?php $arr=array( array('amount'=>100,'date'=>'2014-03-29'), array('amount'=>120,'date'=>'2014-03-30'), array('amount'=>200,'date'=>'2014-03-31') ); usort($arr, function($a, $b) { if($a['date'] == $b['date']) return 0; return $a['date'] > $b['date'] ? 1 : -1; }); var_dump($arr); $amount = 0; foreach($arr as &$item) { $amount += $item['amount']; $item['amount'] = $amount; } var_dump($arr);