public function keyedArray($subject) : bool
    {
        if (!is_array($subject)) {
            return false;
        }
        if (!$subject) {
            return true;
        }
        return !ctype_digit(join('', array_keys($subject)));
    }
public function keyedArray($subject) : bool
    {
        if (!is_array($subject)) {
            return false;
        }
        if (!$subject) {
            return true;
        }
        return !ctype_digit(join('', array_keys($subject)));
    }
public function keyedArray ( $ subject ) : bool { if ( ! is_array ( $ subject ) ) { return false ; } if ( ! $ subject ) { return true ; } return ! ctype_digit ( join ( '' , array_keys ( $ subject ) ) ) ; }
Empty array or keyed array.

@param mixed $subject

@return bool
True: empty array, or at least one key is not integer.
Empty array or keyed array .