get total of multidimensional array

Question

So i have an array which is created like this via a loop

foreach ($items as $item)
{
    $item_arr[$id]['count'] = $item->rowcount;
}

Now what i want to do is get the sum of the counts. I know i can just use $sum += $item->rowcount; but i was wondering if there was a more efficient way using something like this outside the loop when the foreach is done:

$sum = array_sum($item_arr[]['count']);

But that doesn't work says it doesn't like [], is there a way to do it or is the best way just to keep count in the foreach loop. Just would like to keep the code cleaner and more readable but maybe its a stupid question?

Possible duplicate of [multidimensional array array\_sum](http://stackoverflow.com/questions/12838729/multidimensional-array-array-sum) — JstnPwll, Nov 17 '15 at 15:01
Unless this is really a bottleneck in your application do not optimize. See http://c2.com/cgi/wiki?PrematureOptimization — David, Nov 17 '15 at 15:02
If you’re doing the loop anyway, then calculating the sum inside of it likely will perform better than doing it in a separate step afterwards. (And functions like `array_sum` need to loop over the elements as well, only “internally”.) — CBroe, Nov 17 '15 at 15:05

score 0 · Answer 1 · answered Nov 17 '15 at 15:03

0

Where did $id come from?

the best would be $sum += $item->rowcount;

$sum = 0;
foreach ($items as $item) {
 $sum += $item->rowcount;
}
echo $sum;

answered Nov 17 '15 at 15:03

Mindexperiment

145
1
10

Artem Chernov · Answer 2 · 2015-11-17T15:09:12.017

0

You can use array_reduce() like this

function sum($carry, $item){
    return $carry + $item['count'];
}
array_reduce($item_arr, "sum");

edited Nov 17 '15 at 15:09

answered Nov 17 '15 at 15:05

Artem Chernov

856
2
8
26

`return $carry + $item['count'];` – deceze Nov 17 '15 at 15:07
@deceze if you think this way is best. i edited my answer – Artem Chernov Nov 17 '15 at 15:10
Well, I'd actually go one step further: `array_reduce($item_arr, function ($carry, $item) { return $carry + $item['count']; })`. – deceze Nov 17 '15 at 15:12
@deceze i think it is not flexibility – Artem Chernov Nov 17 '15 at 15:18
if in my code will be some place where i call array_reduce($item_arr, "sum"); – Artem Chernov Nov 17 '15 at 15:22

score 0 · Answer 3 · answered Nov 17 '15 at 15:18

A variation of a theme perhaps but like array_reduce you could alternatively use array_walk

$total=0;
$arr=array(
    array('count'=>23),
    array('count'=>54),
    array('count'=>91),
    array('count'=>86)
);

array_walk( $arr, function( &$i, $k, &$t ){
    $t += $i['count'];
}, &$total );

echo 'total:'.$total;

get total of multidimensional array

3 Answers3