Copy Two Dimensional ArrayList as new

Question

So the issue I\'m having is after copying the 2d arraylist, changing the element from one 2d arraylist affects the other 2d arraylist. I want them to be completely separate

Answer 1

I guess I was looking for something like this...

import java.util.ArrayList;
public class QuickTest {
    public static ArrayList> getTwoDimArrListCopy(ArrayList> original){
        ArrayList> copy = new ArrayList<>();

        for (ArrayList arr: original){
            copy.add(new ArrayList(arr));
        }

        return copy;
    }

    public static void main(String[] args) {
        ArrayList> firstTwoDimList = new ArrayList<>();
        ArrayList> secondTwoDimList = new ArrayList<>();

        firstTwoDimList.add(new ArrayList());
        firstTwoDimList.add(new ArrayList());
        firstTwoDimList.add(new ArrayList());

        Integer counter = 2;
        for(int arrI = 0; arrI < firstTwoDimList.size(); arrI++, counter+=2){
            firstTwoDimList.get(arrI).add(counter);
            counter+=2;
            firstTwoDimList.get(arrI).add(counter);
        }

        secondTwoDimList = getTwoDimArrListCopy(firstTwoDimList);

        System.out.println("firstTwoDimList.get(1).get(0) = " + firstTwoDimList.get(1).get(0));
        System.out.println("secondTwoDimList.get(1).get(0) = " + secondTwoDimList.get(1).get(0));

        firstTwoDimList.get(1).set(0, 7);

        System.out.println("firstTwoDimList.get(1).get(0) = " + firstTwoDimList.get(1).get(0));
        System.out.println("secondTwoDimList.get(1).get(0) = " + secondTwoDimList.get(1).get(0));
    }
}

I was just hoping there was a built in library that would do that getTwoDimArrListCopy() function for me...