- var_dump: documentation ( source)
<?php
$obj = new SplObject();
$obj->id = ['a', 'b', 'a', 'c'];
$obj->type = ['aaa', 'bbb', 'aaa', 'aaa'];
$obj->num = [95, 100, 50, 11];
$sum = [];
foreach($obj->id as $idx => $id) {
if(!array_key_exists($id, $sum)) {
$sum[$id] = [];
}
$sum[$obj->type[$id]] += $obj->num;
}
var_dump($sum);