Question

We gave a given array which can be in 4 states.

array has values that are:

• only arrays
• only non-arrays
• both array and non array
• array has no values

Answer 1

Some precalculation:

function isArray($reducedValue, $currentValue) {
    // boolean value is converted to 0 or 1
    return $reducedValue + is_array($currentValue);
}

$number_of_arrays = array_reduce($array, 'isArray', 0);

Then the different states can be evaluated as follows:

1. only arrays

   count($array) == $number_of_arrays
   

2. only non-arrays

   $number_of_arrays == 0
   

3. both array and non array keys

   count($array) != $number_of_arrays
   

4. array has no keys

    empty($array);
   

So you just need to write a function that returns the appropriate state.

Reference: in_array, array_reduce, empty