Get total sum of repeating IDs stored in multidimensional array

Question

I have a multidimensional array of items added to cart in codeigniter. Lets say I order food for me and several friends (specific IDs stored in next level array). Now in case someone has more items I need to get total sum of each friend and save it as money owned to me. How to loop all items to get total sum of each friend with same ID (I cannot move the friend ID to parent array). I store them to database in a way we can see in the table below in non-repeating way. I need a new array to get results like this(to store/update them).

friend_id	amount_owned
52	35
28	5
friend_id 0 is me...we skip me != 0

Array
(
    [array] => Array
        (
    [carthashid1] => Array
                (
                    [0] => Array
                        (
                            [foodid] => 322
                            [price] => 5
                            [name] => Chicken Burger
                            [options] => Array
                                (
                                    [friend_id] => 52
                                    [special_instructions] => 
                                )
                            [rowid] => ceec8698316fe95ec9d7dccf961f32c1
                            [num_added] => 5
                            [sum_price] => 25
                        )

                    [1] => Array
                        (
                            [foodid] => 323
                            [price] => 5
                            [name] => Beef Burger
                            [options] => Array
                                (
                                    [friend_id] => 52
                                    [special_instructions] => 
                                )

                            [rowid] => c2d1c15d159123d1cbdce967785ef06e
                            [num_added] => 2
                            [sum_price] => 10
                        )

                    [2] => Array
                        (
                            [foodid] => 322
                            [price] => 5
                            [name] => Chicken Burger
                            [options] => Array
                                (
                                    [friend_id] => 28
                                    [special_instructions] => 
                                )
                            [rowid] => 3daa7b14b23a5c0afa9b196ea6e35227
                            [num_added] => 1
                            [sum_price] => 5
                        )

                    [3] => Array
                        (
                            [foodid] => 323
                            [price] => 5
                            [name] => Beef Burger
                            [options] => Array
                                (
                                    [friend_id] => 0
                                    [special_instructions] => 
                                )
                            [rowid] => 734c9cc82cf35e2dcc42f28d96a8ebde
                            [num_added] => 1
                            [sum_price] => 5
                        )

                )

        )
    [finalSum] => 45
    [finalItemsCount] => 9
)

Answer 1

It would have taken me less time to check my answer if I didnt have to Hand Code the array, but here it is anyway

$input = [
    'array' => [
        'carthashid1' => [
            [
                'foodid' => 322, 'price' => 5,
                'name' => 'Chicken Burger', 
                'options' => ['friend_id' => 52, 'special_instructions' => ''],
                'rowid' => 'ceec8698316fe95ec9d7dccf961f32c1', 'num_added' => 5,'sum_price' => 25
            ],
            [
                'foodid' => 322, 'price' => 5,
                'name' => 'Beef Burger',
                'options' => ['friend_id' => 52,'special_instructions' => ''],
                'rowid' => 'ceec8698316fe95ec9d7dccf961f32c1', 'num_added' => 2,'sum_price' => 10
            ],
            [
                'foodid' => 322,'price' => 5,'name' => 'Chicken Burger',
                'options' => ['friend_id' => 28,'special_instructions' => ''],
                'rowid' => 'ceec8698316fe95ec9d7dccf961f32c1', 'num_added' => 1,'sum_price' => 5
            ],
            [
                'foodid' => 322, 'price' => 5, 'name' => 'Beef Burger',
                'options' => ['friend_id' => 0,'special_instructions' => ''],
                'rowid' => 'ceec8698316fe95ec9d7dccf961f32c1', 'num_added' => 1, 'sum_price' => 5
            ]
        ]
    ]
];

$friends = [];
foreach($input['array']['carthashid1']  as $ordered){
    if ($ordered['options']['friend_id'] == 0) {
        // its me, ignore me
        continue;
    }
    if ( ! isset($friends[$ordered['options']['friend_id']]) ) {
        // initialise the accumulator for this friend
        $friends[$ordered['options']['friend_id']] = 0; 
    } 
    $friends[$ordered['options']['friend_id']] += $ordered['sum_price'];    
}

print_r($friends);

RESULT

Array
(
    [52] => 35
    [28] => 5
)