Answer by Ja͢ck for Sum values in one column of a 2d array

You need to couple it with array_map() to select the f_count column first:

array_sum(array_map(function($item) {     return $item['f_count']; }, $arr));

Nowadays you can replace the inner function with array_column():

array_sum(array_column($arr, 'f_count'));

Of course, internally, this performs a double loop; it's just that you don't see it inside the code. You could use array_reduce() to get rid of one loop:

array_reduce($arr, function(&$res, $item) {    return $res + $item['f_count'];}, 0);

However, if speed is the only interest, foreach remains the fastest:

$sum = 0;foreach ($arr as $item) {    $sum += $item['f_count'];}

This is thanks to the "locality" of the variables that you're using, i.e. there are no function calls used to calculate the final sum.