PHP多维数组求和并使其唯一[重复]

Question

This question already has an answer here:

• Associative array, sum values of the same key 4 answers

Following is my array. I need to add its Sum field according to each emp_firstname. Some has only one time coming, some coming two times. how can we sum the field and make the array unique?

Array
(
    [0] => Array
        (
            [emp_firstname] => Alistair
            [non_pm] => AMZ
            [sum] => 2
        )


    [1] => Array
        (
            [emp_firstname] => Shakkeer
            [non_pm] => SHK
            [sum] => 3
        )

    [2] => Array
        (
            [emp_firstname] => Waqas
            [non_pm] => WAS
            [sum] => 12
        )

    [3] => Array
        (
            [emp_firstname] => Zain
            [non_pm] => ZAI
            [sum] => 9
        )


    [4] => Array
        (
            [emp_firstname] => Shakkeer
            [gud_pmeditor] => SHK
            [sum] => 4
        )

    [5] => Array
        (
            [emp_firstname] => Zain
            [gud_pmeditor] => ZAI
            [sum] => 2
        )

)

</div>

Answer 1

You can get the desired result using this approach

$res=[];
foreach($arr as $val){
  if(array_key_exists($val['emp_firstname'], $res))
    $res[$val['emp_firstname']]['sum'] = ($res[$val['emp_firstname']]['sum'] + $val['sum']);
  else
    $res[$val['emp_firstname']] = $val;
}

Live Demo