Online PHP editor | refs for AfPEp

<?php $array = [ '2015-09-23' => [ 'user' => [13, 12], 'count' => [ 'count' => 2, 'total' => 2, ], ], '2015-09-24' => [ 'user' => [14], 'count' => [ 'count' => 1, 'total' => 1, ], ], '2015-09-25' => [ 'user' => [15], 'count' => [ 'count' => 1, 'total' => 1, ], ], '2015-09-26' => [ 'user' => [16], 'count' => [ 'count' => 1, 'total' => 1, ], ], '2015-09-27' => [ 'user' => [17, 18], 'count' => [ 'count' => 2, 'total' => 2, ], ], '2015-09-28' => [ 'user' => [19, 20, 21, 22, 23, 24, 25, 26, 27, 28], 'count' => [ 'count' => 10, 'total' => 10, ], ], ]; $total = 0; foreach ($array as ['count' => ['count' => $c, 'total' => &$t]]) { $total += $c; $t = $total; } var_export($array);