Sum of duplicate key values array in PHP

Question

I have an array with duplicate key values. How can I sum all duplicate array key values in another new array?

 $array = Array (
           "0" => Array ( "2" => 123 ),
           "1" => Array ( "4" => 45 ),
           "2" => Array ( "3" => 12 ),
           "3" => Array ( "5" => 2 ),
           "4" => Array ( "2" => 12 ),
           "5" => Array ( "4" => 21 ),
           "6" => Array ( "2" => 12 ),
           "7" => Array ( "3" => 21 ),
           "8" => Array ( "2" => 12 ),
           "9" => Array ( "3" => 21 ),
           "10" => Array ( "2" => 2 ),
           "11" => Array ( "4" => 2 ),
           "12" => Array ( "2" => 2 ),
           "13" => Array ( "4" => 2 ),
           "14" => Array ( "3" => 12 ),
           "15" => Array ( "4" => 12 ),
           "16" => Array ( "2" => 12 ),
           "17" => Array ( "2" => 12 ),
           "18" => Array ( "4" => 12 ),
           "19" => Array ( "3" => 12 ),
           "20" => Array ( "2" => 15 ),
           "21" => Array ( "4" => 21 ),
   );

Output will looks like

$newArray = Array
  (
    [2] => 202
    [3] => 78
    [4] => 115
    [5] => 2
  )

looks more like not duplicate values but like you wanna sum values by keys — ArtOsi, Dec 19 '17 at 07:22

score 3 · Accepted Answer · answered Dec 19 '17 at 08:00

You can use array_sum and array_column to get the sums of each.

First we have to get all the keys then sum them with array_sum and array_column.

$arr = Array (
    "0" => Array ( "2" => 123 ),
    "1" => Array ( "4" => 45 ),
    "2" => Array ( "3" => 12 ),
    "3" => Array ( "5" => 2 ),
    "4" => Array ( "2" => 12 ),
    "5" => Array ( "4" => 21 ),
    "6" => Array ( "2" => 12 ),
    "7" => Array ( "3" => 21 ),
    "8" => Array ( "2" => 12 ),
    "9" => Array ( "3" => 21 ),
    "10" => Array ( "2" => 2 ),
    "11" => Array ( "4" => 2 ),
    "12" => Array ( "2" => 2 ),
    "13" => Array ( "4" => 2 ),
    "14" => Array ( "3" => 12 ),
    "15" => Array ( "4" => 12 ),
    "16" => Array ( "2" => 12 ),
    "17" => Array ( "2" => 12 ),
    "18" => Array ( "4" => 12 ),
    "19" => Array ( "3" => 12 ),
    "20" => Array ( "2" => 15 ),
    "21" => Array ( "4" => 21 ),
);

// find all subarray keys (2,3,4,5)
foreach($arr as $subarr){
    $keys[] = key($subarr);
}

// remove duplicate keys
$keys = array_unique($keys);

// sum values with same key from $arr and save to $sums
foreach($keys as $key){
    $sums[$key] = array_sum(array_column($arr,$key));    
}

var_dump($sums);

https://3v4l.org/F3RJr

The code can be made shorter like this:

foreach($arr as $subarr){
    $key = key($subarr);
    if(!isset($sums[$key])){
        $sums[$key] = array_sum(array_column($arr,$key));        
    }
}
var_dump($sums);

but I'm not sure it's faster. Maybe...

score 1 · Answer 2 · answered Dec 19 '17 at 07:31

1

You can use array_walk_recursive()

$result = [];

array_walk_recursive($array, function($v, $k) use (&$result) {
    if (!isset($result[$k])) {
        $result[$k] = $v;
    } else {
        $result[$k] += $v;
    }
});

print_r($result);

answered Dec 19 '17 at 07:31

Goma

2,018
1
10
19

Code Lღver · Answer 3 · 2017-12-19T07:38:58.567

Check the below code.

$output = array();
$keyarray = array();
foreach($arr as $key => $val){
    if(is_array($val)){
        $key = key($val);
        if(in_array($key,$keyarray)) {
            $output[$key] = $output[$key]+$val[$key];
        } else {
            $keyarray[] = $key;
            $output[$key] = $val[$key];
        }
    }
}

print_r($output);

print_r($output); will give you the expected result.

Sum of duplicate key values array in PHP

3 Answers3