HomeLanguagesJavaArrayList of ArrayList in Java

ArrayList of ArrayList in Java

We have discussed that an array of ArrayList is not possible without warning. A better idea is to use ArrayList of ArrayList.




// Java code to demonstrate the concept of
// array of ArrayList
  
import java.util.*;
public class Arraylist {
    public static void main(String[] args)
    {
        int n = 3;
  
        // Here aList is an ArrayList of ArrayLists
        ArrayList<ArrayList<Integer> > aList = 
                  new ArrayList<ArrayList<Integer> >(n);
  
        // Create n lists one by one and append to the 
        // master list (ArrayList of ArrayList)
        ArrayList<Integer> a1 = new ArrayList<Integer>();
        a1.add(1);
        a1.add(2);
        aList.add(a1);
  
        ArrayList<Integer> a2 = new ArrayList<Integer>();
        a2.add(5);
        aList.add(a2);
  
        ArrayList<Integer> a3 = new ArrayList<Integer>();
        a3.add(10);
        a3.add(20);
        a3.add(30);
        aList.add(a3);
  
        for (int i = 0; i < aList.size(); i++) {
            for (int j = 0; j < aList.get(i).size(); j++) {
                System.out.print(aList.get(i).get(j) + " ");
            }
            System.out.println();
        }
    }
}


Output:

1 2 
5 
10 20 30
RELATED ARTICLES

3 COMMENTS

Most Popular

Dominic
32688 POSTS0 COMMENTS
Milvus
131 POSTS0 COMMENTS
Nango Kala
7057 POSTS0 COMMENTS
Nicole Veronica
12198 POSTS0 COMMENTS
Nokonwaba Nkukhwana
12293 POSTS0 COMMENTS
Shaida Kate Naidoo
7182 POSTS0 COMMENTS
Ted Musemwa
7447 POSTS0 COMMENTS
Thapelo Manthata
7160 POSTS0 COMMENTS
Umr Jansen
7150 POSTS0 COMMENTS