Question

How to initialize and print sublists of multiple ArrayLists (List of Lists) in Java

Answer 1

import java.util.ArrayList;
import java.util.List;
  
public class MyClass {
    public static void main(String args[]) {
 
        List<List<String>> listOfLists = new ArrayList<>();
 
        List<String> subList1 = new ArrayList<>();
        subList1.add("c#");
        subList1.add("c++");
 
        List<String> subList2 = new ArrayList<>();
        subList2.add("c");
        subList2.add("java");
        subList2.add("php");
 
        listOfLists.add(subList1);
        listOfLists.add(subList2);
  
        System.out.println(listOfLists);
        System.out.println();
        
        for(List<String> sub : listOfLists) {
            System.out.println(sub);
        }  
        System.out.println();

          
        for(List<String> sub : listOfLists) {
            System.out.println(sub.get(0) + "  " + sub.get(1));
        } 
        System.out.println();

        listOfLists.forEach(innerList -> {
            String sub = String.join(", ", innerList);
            System.out.println(sub);
        });
    }
}
    
    
    
    
/*
run:
    
[[c#, c++], [c, java, php]]

[c#, c++]
[c, java, php]

c#  c++
c  java

c#, c++
c, java, php
    
*/

 

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