- array_map: documentation ( source)
- array_sum: documentation ( source)
- print_r: documentation ( source)
<?php
$data = [
9 => [
1 => [2 => 433, 6 => 2, 4 => 101],
3 => [6 => 999],
],
14 => [
2 => [2 => 0, 6 => 2],
]
];
$result = array_map(fn($v) => array_sum(array_map(fn($v) => array_sum($v), $v)), $data);
print_r($result);