将数组存储在2d数组Java中

Question

So why doesn't this work? Not really sure why this isn't possible- I just want to store an array of size 2 inside a 2d array.

I know this would be equivalent to setting storage[0][0] = array[0] and storage[0][1] = array[1], but just wondering why this is incorrect.

public class Test {

    public static void main(String[] args) {
        boolean[][] storage = new boolean[10][2];
        boolean[] array = new boolean[2];
        array[0] = true;
        array[1] = false;

        storage[0][] = array; //Why can't I do this?
    }
}

Thanks in advance

Answer 1

You have a stray pair of brackets in your assignment. Just use

storage[0] = array;

Answer 2

First of all boolean[][] storage = new boolean[10][2] declares an array and initialise it.

So, you have created 11 arrays. One of boolean[] element type and 10 of boolean type .

It's good, If you want to access it's members directly, but if you create an inner array lately with new boolean[] , it's an overhead.

Use boolean[][] storage = new boolean[10][]; instead.

Then, you can access it's elements, which are boolean[] type, and assign your array to it.

storage[0] = array;

Answer 3

Your problem is the stray square brackets(as I'm sure you know). Your code should look like this:

storage[0] = array;

The previous answers did not really explain why though, so that's what I'll do.

What your trying to do is make the first position( storage[0] ) hold the same value as array . array is 1 dimensional, so it can only be part of storage , which is 2 dimensional.