CODEWITHSUNDEEP
phparraysmultidimensional-arraysumgrouping
PontusTrade
PontusTrade

Reputation: 85

Group a 2d array's row data by one column and sum another column per group

Problem: Find the sum of the values in 'subtotal' for each 'id' and store the respective sum for each id in an array (or variables).

My sloppy solution at the moment is to run a foreach with multiple if statements inside that count the occurrences. This is adequate for something like 5 ids, but I have to iterate this over 38 ids. I would like to store the results sequentially in an array if possible.

How can I make it more efficient? Any and all help will be appreciated. (See my sloppy solution at the end of this for a good chuckle)

Desired Result:

Array Code for Manipulation 

    $someArray = array(

    array(
        'id'=> 1,
        'subtotal'=> 5),
    array(
        'id'=> 1,
        'subtotal'=> 5),
    array(
         'id'=> 2,
         'subtotal'=> 6), 
    array(
         'id'=> 2,
         'subtotal'=> 6),
    array(
         'id'=> 2,
         'subtotal'=> 6),
    array(
         'id'=> 3,
         'subtotal'=> 7),
    array(
         'id'=> 3,
         'subtotal'=> 7),
    array(
         'id'=> 4,
         'subtotal'=> 2),
    array(
         'id'=> 4, 
         'subtotal'=> 2),
    array(
         'id'=> 5,
         'subtotal'=> 3),
    );

Sloppy Solution

$sum_id_1 = 0;
$sum_id_2 = 0;
$sum_id_3 = 0;
$sum_id_4 = 0;
$sum_id_5 = 0;

foreach ($someArray as $k) {

    if ($k['id'] == 1) {
        $sum_id_1 += $k['subtotal'];
    }

    if ($k['id'] == 2) {
        $sum_id_2 += $k['subtotal'];
    }

    if ($k['id'] == 3) {
        $sum_id_3 += $k['subtotal'];
    }

    if ($k['id'] == 4) {
        $sum_id_4 += $k['subtotal'];
    }

    if ($k['id'] == 5) {
        $sum_id_5 += $k['subtotal'];
    }
}

Sloppy Solution Output (on echo)

Upvotes: 2

Views: 6741

Answers (2)

Melon
Melon

Reputation: 1

$arr3 = array (
"0" => array ( "001" => 10 ),
"1" => array ( "005" => 20 ),
"2" => array ( "001" => 30 ),
"3" => array ( "003" => 20 ),
"4" => array ( "005" => 80 ),
"5" => array ( "001" => 90 ),
"6" => array ( "003" => 20 ),
"7" => array ( "006" => 80 ),
"8" => array ( "006" => 90 )
) ;

 array (size=4)
   0 => 
      array (size=1)
        '001' => int 130
   1 => 
      array (size=1)
        '005' => int 100
   2 => 
      array (size=1)
       '003' => int 40
   3 => 
      array (size=1)
       '006' => int 170

$outer_array = array();
$unique_array = array();
$inner_array = array();
  foreach($arr3 as $key => $value)
  {

  $item = key($value);
  if(!in_array(key($value), $unique_array))
  {
     array_push($unique_array, $item);
     $inner_array[key($value)] = $value[$item];
     $outer_array[$item][$item] = $value[$item];

  }else{
    $inner_array[key($value)] = $value[$item] + $inner_array[$item];
    $outer_array[$item][$item] = $inner_array[$item];
  }
}
 var_dump(array_values($outer_array));

if you want to sum up all the values with the same key.namely, the above result is what you hope.so my answer is approaching……that is all, wish will help somebody encountering the same situation about this question!

Upvotes: 0

zerkms
zerkms

Reputation: 254886

$sum = array_reduce($someArray, function($result, $item) {
    if (!isset($result[$item['id']])) $result[$item['id']] = 0;
    $result[$item['id']] += $item['subtotal'];
    return $result;
}, array());

var_dump($sum); // array(5) { [1]=> int(10) [2]=> int(18) [3]=> int(14) [4]=> int(4) [5]=> int(3) }

For PHP <= 5.3 perform the counting in loop manually:

$sum = array();

foreach ($someArray as $item) {
    if (!isset($sum[$item['id']])) $sum[$item['id']] = 0;
    $sum[$item['id']] += $item['subtotal'];
}

Upvotes: 8

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