How to store a 2D array in a regular array? Java

Question

basically I want to be able to store a 2D array such as this

int [][] preferredMoves = {
            {0,0}, {0, arrLength}, {length%2, arrLength},
            {0, length%2}, {arrLength, 0}, {0, length%2}, 
            {arrLength, arrLength}, {length%2, length%2},
            {arrLength, length%2}, {length%2, 0}
    };

In a single

int [] moves;

array.

I'm sure this is possible since I'm just storing a list..., but I can't seem to find information on this anywhere... or maybe its not possible?

EDIT I am dealing with matrices. I want to store the list in a single array to then return that array to use it elsewhere.

So then every time I call it, all I have to do is something like this...

int row = Computer.moves()[0];
    int col = Computer.moves()[1];

I also need to loop through that single array, which contains the 2D array multiple times..

What keeps you from using an ArrayList<int[][]>?

Hips
– Hips

2015-10-02 22:17:15 +00:00
Commented Oct 2, 2015 at 22:17 — Hips
– Hips, Commented Oct 2, 2015 at 22:17
you actually gave me an idea @Hips

user2831805
– user2831805

2015-10-02 22:42:15 +00:00
Commented Oct 2, 2015 at 22:42 — user2831805
– user2831805, Commented Oct 2, 2015 at 22:42

janos · Accepted Answer · 2015-10-02 22:13:03Z

3

Not sure if this is what you meant, but you could drop the internal { ... } to convert this to a one-dimensional array:

int [] moves = {
        0, 0, 0, arrLength, length % 2, arrLength,
        0, length % 2, arrLength, 0, 0, length % 2, 
        arrLength, arrLength, length % 2, length % 2,
        arrLength, length % 2, length % 2, 0
};

And you can translate 2D indexes (i, j) to 1D index k using the formula:

k = i * 2 + j;

answered Oct 2, 2015 at 22:13

janos

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3 Comments

user2831805 Over a year ago

I don't quite understand this, would you mind explaining a little?

janos Over a year ago

I don't quite understand your question. Can you please add more examples of your desired behavior?

user2831805 Over a year ago

Well I wanted to add that List to another List in order to loop through it as many times as I needed. I used an ArrayList<int[]> to do this. But then it got messy because I also wanted length to decrement which is impossible and I didn't realize until last minute... I had to redo my method a different way. Thanks though! @janos

Kip · Accepted Answer · 2015-10-02 22:22:55Z

0

Janos' answer is probably what you want. Alternatively you could create a class, e.g. Pair, and store it in a Pair[] array.

answered Oct 2, 2015 at 22:22

Kip

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