convert flat array into multidimensional array in php - php

Question

I am trying to convert a flat array into multidimensional array based on 'parent' and look a lot of examples and get good results but have 1 issue. I am missing last time of the array.
first i created an flat array
$service_arr = array();
foreach( $order_info[0]['service'] as $ordered_service ) {
$s_id = $ordered_service['id'];
$s_name = $ordered_service['name'];
$s_qty = $ordered_service['qty'];
$s_price = $ordered_service['price'];
$s_parent = gp_get_item_parent( $s_id ); // return parent_id of the element.
$service_arr[] = array(
'id' => $s_id,
'name' => $s_name,
'qty' => $s_qty,
'price' => $s_price,
'parent' => $s_parent
);
}
and this return's a flat array
Result:
Array
(
[0] => Array
(
[id] => 29
[name] => Another Facial
[qty] => 1
[price] => 1800
[parent] => 16
)
[1] => Array
(
[id] => 17
[name] => Facial 1
[qty] => 1
[price] => 2000
[parent] => 16
)
[2] => Array
(
[id] => 26
[name] => Addon
[qty] => 1
[price] => 500
[parent] => 17
)
[3] => Array
(
[id] => 39
[name] => Another Addon
[qty] => 1
[price] => 150
[parent] => 17
)
[4] => Array
(
[id] => 18
[name] => Facial 2
[qty] => 1
[price] => 2000
[parent] => 16
)
[5] => Array
(
[id] => 38
[name] => Nice Facial
[qty] => 1
[price] => 3000
[parent] => 16
)
[6] => Array
(
[id] => 21
[name] => Massage 2
[qty] => 1
[price] => 6000
[parent] => 14
)
)
Converting flat into multidimension array:
function create_tree_array( &$list, &$output, $parent_id ) {
if ( ! is_array( $list ) ) {
return;
}
if ( ! is_array( $output ) ) {
return;
}
foreach( $list as $i => $item ) {
if ( $item['parent'] == $parent_id ) {
$item['addon'] = array();
create_tree_array( $list, $item['addon'], $item['id'] );
$output[] = $item;
}
}
}
And using this function like
$services_tree = array();
create_tree_array( $service_arr, $services_tree, $service_arr[0]['parent'] );
Its working but the issue is that its missing last item of array:
[6] => Array (
[id] => 21
[name] => Massage 2
[qty] => 1
[price] => 6000
[parent] => 14
)