Join two ArrayLists in Java
Given two ArrayLists in Java, the task is to join these ArrayLists.
Examples:
Input: ArrayList1: [Geeks, For, ForGeeks], ArrayList2: [GeeksForGeeks, A computer portal]
Output: ArrayList: [Geeks, For, ForGeeks, GeeksForGeeks, A computer portal]Input: ArrayList1: [G, e, e, k, s], ArrayList2: [F, o, r, G, e, e, k, s]
Output: ArrayList: [G, e, e, k, s, F, o, r, G, e, e, k, s]
Approach: ArrayLists can be joined in Java with the help of Collection.addAll() method. This method is called by the destination ArrayList and the other ArrayList is passed as the parameter to this method. This method appends the second ArrayList to the end of the first ArrayList.
Syntax:
ArrayList1.addAll(ArrayList2);
Below is the implementation of the above approach:
// Java program to demonstrate // How to sort ArrayList in descending order import java.util.*; public class GFG { public static void main(String args[]) { // Get the ArrayList1 ArrayList<String> list1 = new ArrayList<String>(); // Populate the ArrayList list1.add("Geeks"); list1.add("For"); list1.add("ForGeeks"); // Print the ArrayList 1 System.out.println("ArrayList 1: " + list1); // Get the ArrayList2 ArrayList<String> list2 = new ArrayList<String>(); list2.add("GeeksForGeeks"); list2.add("A computer portal"); // Print the ArrayList 2 System.out.println("ArrayList 2: " + list2); // Join the ArrayLists // using Collection.addAll() method list1.addAll(list2); // Print the joined ArrayList System.out.println("Joined ArrayLists: " + list1); } } |
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