- var_dump: documentation ( source)
- usort: documentation ( source)
<?php
$arr=array(
array('amount'=>100,'date'=>'2014-04-29'),
array('amount'=>120,'date'=>'2014-03-30'),
array('amount'=>200,'date'=>'2014-03-31')
);
usort($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);