The array_column function iteratively reduces the array to a single value using a callback function.

    
    function sum($carry, $item)
    {
        $carry += $item;
        return $carry;
    }

    $a = array(1, 2, 3, 4, 5);

    $sum =array_reduce($a, "sum");

    echo $sum;
    // int(15)