Question

How to create dynamic 2D ArrayList in java

Answer 1

import java.util.ArrayList;
import java.util.List;

public class MyClass {
    public static void main(String args[]) {
        List<int[]> li = new ArrayList<>();
        
        li.add(new int[]{6, 8, 1});
        li.add(new int[]{9, 3});
        li.add(new int[]{2});
        
        System.out.println("Element [0][0]: " + li.get(0)[0]);
        System.out.println("Element [0][1]: " + li.get(0)[1]);
        System.out.println("Element [0][1]: " + li.get(0)[2]);
        
        System.out.println("Element [0][1]: " + li.get(1)[0]);
        System.out.println("Element [0][1]: " + li.get(1)[1]);
        
        System.out.println("Element [0][1]: " + li.get(2)[0]);
    }
}
 
 
 
/*
run:
 
Element [0][0]: 6
Element [0][1]: 8
Element [0][1]: 1
Element [0][1]: 9
Element [0][1]: 3
Element [0][1]: 2
 
*/

 

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Answer 2

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class MyClass {
    public static void main(String args[]) {
        List<int[]> li = new ArrayList<>();
        
        li.add(new int[]{6, 8, 1});
        li.add(new int[]{9, 3});
        li.add(new int[]{2});
        
        for (int[] row : li) {
            System.out.println("Row = " + Arrays.toString(row));
        } 
    }
}
 
 
 
/*
run:
 
Row = [6, 8, 1]
Row = [9, 3]
Row = [2]
 
*/

 

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Answer 3

import java.util.ArrayList;
import java.util.List;

public class MyClass {
    public static void main(String args[]) {
        List<int[]> li = new ArrayList<>();
        
        li.add(new int[]{6, 8, 1});
        li.add(new int[]{9, 3});
        li.add(new int[]{2});
        
        for (int i = 0; i < li.size(); i++) {
            int[] arr = new int[3]; 
            arr = li.get(i);
            for (int j = 0;j < arr.length; j++) {
                System.out.printf("%2d", arr[j]); 
            }
            System.out.println();
        }   
    }
}
 
 
 
/*
run:
 
 6 8 1
 9 3
 2
 
*/

 

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