JBZoo\Utils\Arr::isAssoc PHP Method

    public static function isAssoc($array)
    {
        return array_keys($array) !== range(0, count($array) - 1);
    }

 public function testIsAssoc()
 {
     isFalse(Arr::isAssoc(array('a', 'b', 'c')));
     isFalse(Arr::isAssoc(array("0" => 'a', "1" => 'b', "2" => 'c')));
     isTrue(Arr::isAssoc(array("1" => 'a', "0" => 'b', "2" => 'c')));
     isTrue(Arr::isAssoc(array("a" => 'a', "b" => 'b', "c" => 'c')));
 }