Group qualifying multidimensional array data and sum a column of values

Question

I have an array with dynamic values. The goal is to merge the subarrays which have same code and sum of cost value with same code.

$array = [
    [
        ['code'=>'AA', 'name'=>'A Name', 'cost'=>'10'],
        ['code'=>'AB', 'name'=>'B Name', 'cost'=>'15'],
    ],
    [
        ['code'=>'AA', 'name'=>'A Name', 'cost'=>'15'],
        ['code'=>'AB', 'name'=>'B Name', 'cost'=>'10'],
        ['code'=>'AC', 'name'=>'C Name', 'cost'=>'10'],
    ],
    [
        ['code'=>'AA', 'name'=>'A Name', 'cost'=>'5'],
        ['code'=>'AB', 'name'=>'B Name', 'cost'=>'10'],
        ['code'=>'AC', 'name'=>'C Name', 'cost'=>'15'],
    ]
];

Desired result:

[
    [
        ['code'=>'AA', 'name'=>'A Name', 'cost'=>'30'],
        ['code'=>'AB', 'name'=>'B Name', 'cost'=>'35'],
    ]
]

The result is only code AA and BB because code AC not exist on first index. Then cost values within each group are summed.

Answer 1

Demo

$array = array(
            array(
                array(
                    'code'=>'AA',
                    'name'=>'A Name',
                    'cost'=>'10',
                ),
                array(
                    'code'=>'AB',
                    'name'=>'B Name',
                    'cost'=>'15',
                ),
            ),
            array(
                array(
                    'code'=>'AA',
                    'name'=>'A Name',
                    'cost'=>'15',
                ),
                array(
                    'code'=>'AB',
                    'name'=>'B Name',
                    'cost'=>'10',
                ),
                array(
                    'code'=>'AC',
                    'name'=>'C Name',
                    'cost'=>'10',
                ),
            ),
            array(
                array(
                    'code'=>'AA',
                    'name'=>'A Name',
                    'cost'=>'5',
                ),
                array(
                    'code'=>'AB',
                    'name'=>'B Name',
                    'cost'=>'10',
                ),
                array(
                    'code'=>'AC',
                    'name'=>'C Name',
                    'cost'=>'15',
                ),
            ),
        );      

        $the_biggest_number=count($array);

        $new_array = array();
        foreach ($array as $key => $val) {

            foreach ($val as $sub_key => $sub_val) {
                if(!isset($new_array[$sub_val['code']])){
                        $sub_val['count']=1;
                        $new_array[$sub_val['code']]=$sub_val;
                }
                else{
                    $new_array[$sub_val['code']]['cost'] += $sub_val['cost'];
                    $new_array[$sub_val['code']]['count'] += 1;
                }
            }
        }        

        $result=array();
        foreach ($new_array as $key => $val) {
            if($val['count']==$the_biggest_number){
                unset($val['count']);
                $result[]=$val;
            }
        }

        $result= array($result);

        echo '<pre>';
        print_r($result);