Checking if array is multidimensional or not?

Question

1. What is the most efficient way to check if an array is a flat array of primitive values or if it is a multidimensional array?

Answer 1

I think this is the most straight forward way and it's state-of-the-art:

function is_multidimensional(array $array) {
    return count($array) !== count($array, COUNT_RECURSIVE);
}