Array sum the same value of element?

Question

How to sum array the same value of element ?

$arr = [
   ['id' => 1, 'qty' => 100, 'name' => 'a'],
   ['id' => 1, 'qty' => 100, 'name' => 'a'],
   ['id' => 2, 'qty' => 100, 'name' => 'b']
];

become to :

$arr = [
   ['id' => 1, 'qty' => 200, 'name' => 'a'],
   ['id' => 2, 'qty' => 100, 'name' => 'b']
];

i was try but return

[ 1=>['qty'=>200], 2=>['qty'=>100] ]

i was try but return

for($i=0; $i<count($cok);$i++){
        $item_id = $cok[$i]['id'];
        $quantity = $cok[$i]['quantity'];
        if (isset($new_items[$item_id])) {
            $new_items[$item_id] = ['quantity' => $new_items[$item_id]['quantity'] + $quantity];
        } else {
            $new_items[$item_id] = ['quantity' => $quantity];
        }
    }

possible duplicate of [Associative array, sum values of the same key](http://stackoverflow.com/questions/14195916/associative-array-sum-values-of-the-same-key) — Thomas, Sep 14 '15 at 22:16
thats same return with what i try, but different with what i want — Donny Gunawan, Sep 14 '15 at 22:22
@DonnyGunawan, you can modify code from selected answer (from Baba) to fit your needs, i would post it as answer, but.... answer already exists... :) — sinisake, Sep 14 '15 at 22:40

score 2 · Accepted Answer · answered Sep 15 '15 at 02:11

Simple as pie (:

<?php
$arr = array(
    array('id' => 1, 'qty' => 100, 'name' => 'a'),
    array('id' => 1, 'qty' => 100, 'name' => 'a'),
    array('id' => 2, 'qty' => 100, 'name' => 'b')
);

$new_arr = array();
foreach($arr AS $item) {
  if(isset($new_arr[$item['id']])) {
    $new_arr[$item['id']]['qty'] += $item['qty'];
    continue;
  }

  $new_arr[$item['id']] = $item;
}

$arr = array_values($new_arr);

var_dump($arr);

score 0 · Answer 2 · answered Sep 15 '15 at 01:41

Dive into my viper

And inplace snippet, returns exactly you need:

<?
$arr = array(
    array('id' => 1, 'qty' => 100, 'name' => 'a'),
    array('id' => 1, 'qty' => 100, 'name' => 'a'),
    array('id' => 2, 'qty' => 100, 'name' => 'b')
);

$ids = array();
foreach ($arr as $i => $subarray) {
    if (!($remove_from_array = array_key_exists($subarray['id'], $ids))) {
        $ids[$subarray['id']] = 0;
    }
    $ids[$subarray['id']] += $subarray['qty'];
    if ($remove_from_array) {
        unset($arr[$i]);
    }
}
foreach ($arr as &$subarray) {
    $subarray['qty'] = $ids[$subarray['id']];
}

print_r($arr);

Array sum the same value of element?

2 Answers2