如何检查数组是否只包含PHP中的其他数组？

Question

I'm looking for a simple way/function to tell me if an array contains only other arrays or if there are values contained as well. For example,

$a = array(array(), array(), array())

should end up with a 'true' result but

$b = array(array(), 1, 17)

should end up with a 'false result.

I know I can do the following,

function isArrayOfArrays($a) {
    foreach ($a as $value) {
        if (!is_array($value))
            return false;
    }
    return true;
}

I'm wondering if there is a more elegant way.

Answer 1

You can try with array_filter:

$isArrayOfArrays = empty( array_filter($b, function($item){
  return !is_array($item);
}) );

Or even shorter:

$isArrayOfArrays = array_filter($b, 'is_array') === $b;