一个数组可以有多个数组吗？

Question

Can I make an array and put another array in it? Like:
var cars = [[sportCars], [luxuryCars], [automaticCars]]
Each of the sportCars luxuryCars automaticCars is an unique array and have a unique elemnts.

Answer 1

Yes, you can, exactly the way you did in your example.

Note that if sportCars , et. al., is an array, the code in your question is adding an extra level by wrapping it in a second array. There's no need to do that, just:

var sportCars = ["Ferrari", "Lamborghini"];
var cars = [sportCars];

...gives you an array containing an array:

console.log(cars[0][0]); // "Ferrari"

You don't need (and probably don't want) the extra [ and ] around sportCars that you have in your question.

Answer 2

You can do it like this:

var sportCars = ['car1', 'car2'];
var luxuryCars = ['car3'];
var automaticCars = ['car4', 'car5'];
var cars = [sportCars, luxuryCars, automaticCars];