Multi dimensional array, sum values of the same key

Question

I have a multi dimensional array. I need to sum up the distance values with same 'driver' and 'date' keys

Input : 

$firstArr = array(
0 =>array('driver'=>'xxxx',
                    'distance' => 100,
                    'vehicle' => 1,
                    'date' => '2019-10'),

1=>array('driver'=>'xxxx',
                    'distance' => 200,
                    'vehicle' => 2,
                    'date' => '2019-10'),
2=>array('driver'=>'yyyy',
                    'distance' => 100,
                    'vehicle' => 3,
                    'date' => '2019-10'));

Output Expected :

$finalArr = array(
0 =>array('driver'=>'xxxx',
                    'distance' => 300,
                    'vehicle' => '1,2',
                    'date' => '2019-10'),

1=>array('driver'=>'yyyy',
                    'distance' => 100,
                    'vehicle' => 3,
                    'date' => '2019-10'));

I tried below code. But the output is a datewise array.

$subArr = array();
foreach($firstArr as $key => $val){
$subArr[$val['driver']][$val['date']]['distance'] += $val['distance'];
$subArr[$val['driver']][$val['date']]['vehicle'] .= $val['vehicle'].',';
$subArr[$val['driver']][$val['date']]['date'] = $val['date'];
$subArr[$val['driver']][$val['date']]['driver'] = $val['driver'];

}
$result = array_values($subArr);

What you have tried so far ? – Rakesh Jakhar Nov 25 '19 at 07:57 — Rakesh Jakhar, Nov 25 '19 at 07:57

score 2 · Accepted Answer · answered Nov 25 '19 at 08:05

You can use the dirver and date as a key, Demo

$result = [];
foreach($array as $v){
    $key = $v["driver"] . "_" . $v["date"];
    if(isset($result[$key])){
        $result[$key]["distance"] += $v["distance"];
    }else{
        $result[$key] = $v;
    }
}
$result = array_values($result);

score 0 · Answer 2 · answered Nov 25 '19 at 09:30

You can also use array_reduce to sum up the distance and the vehicles by driver and date. With the help of array_combine we can set the initial array if not exists for each driver date combo and then do the processing of the required fields.

$keys = array_keys($input[0]);
$result = array_reduce($input, function ($sum, $row) use ($keys) {
    $key = $row['driver'] . $row['date'];
    $sum[$key] = $sum[$key] ?? array_combine($keys, [$row['driver'], null, null, $row['date']]);
    $sum[$key]['distance'] += $row['distance'];
    $sum[$key]['vehicle'] .= (($sum[$key]['vehicle']) ? ',': '' ) . $row['vehicle'];
    return $sum;
}, []);

Results in:

Array
(
    [xxxx2019-10] => Array
        (
            [driver] => xxxx
            [distance] => 300
            [vehicle] => 1,2
            [date] => 2019-10
        )

    [yyyy2019-10] => Array
        (
            [driver] => yyyy
            [distance] => 100
            [vehicle] => 3
            [date] => 2019-10
        )

)

Multi dimensional array, sum values of the same key

2 Answers2