How to Convert all LinkedHashMap Values to a List in Java?
The task is to convert all LinkedHashMap values to a list in java. LinkedHashMap is an implementation of a Map. The Map and List are two different data structures. The Map stores key-value pairs while the List is an ordered collection of elements.
To convert all values of the LinkedHashMap to a List using the values() method. The values() method of the LinkedHashMap class returns a Collection view of all the values contained in the map object. You can then use this collection to convert it to a List object.
Syntax:
LinkedHashMap.values()
Return Value: The method is used to return a collection view containing all the values of the map.
Example 1:
Java
// Java program to Convert all LinkedHashMap values to a// Listimport java.util.ArrayList;import java.util.LinkedHashMap;import java.util.List;public class LinkedHashMapToListExample { public static void main(String[] args) { // instance of linkedhashmap LinkedHashMap<Integer, Integer> lhmap = new LinkedHashMap<Integer, Integer>(); // add mappings lhmap.put(1, 11); lhmap.put(2, 22); lhmap.put(3, 33); // convert values to a list List<Integer> listValues = new ArrayList<Integer>(lhmap.values()); // print values System.out.println("List contains:"); for (Integer value : listValues) { System.out.println(value); } }} |
List contains: 11 22 33
Example 2:
Java
// Java program to Convert all LinkedHashMap values to a// Listimport java.util.ArrayList;import java.util.LinkedHashMap;import java.util.List;public class LinkedHashMapToListExample { public static void main(String[] args) { // instance of linkedhashmap LinkedHashMap<Integer, String> lhmap = new LinkedHashMap<Integer, String>(); // add mappings lhmap.put(10, "Geeks"); lhmap.put(15, "4"); lhmap.put(20, "Geeks"); lhmap.put(25, "Welcomes"); lhmap.put(30, "You"); // convert values to a list List<String> listValues = new ArrayList<String>(lhmap.values()); // print values System.out.println("List contains:"); for (String value : listValues) { System.out.println(value); } }} |
List contains: Geeks 4 Geeks Welcomes You
Another Method : Using List.copyOf()
In java, we can convert the set to list by using List.copyOf(object). For this, we have to import the package java.util.List.*. It is a static factory method which creates the list object from another collection or object.
Java
import java.util.*;class GFG { public static void main (String[] args) { LinkedHashMap<Integer, String> lhmap = new LinkedHashMap<Integer, String>(); // add mappings lhmap.put(10, "Geeks"); lhmap.put(15, "4"); lhmap.put(20, "Geeks"); lhmap.put(25, "Welcomes"); lhmap.put(30, "You"); // convert values to a list List<String> listValues = List.copyOf(lhmap.values()); // print values System.out.println("List contains:"); for (String value : listValues) { System.out.println(value); } }} |
List contains: Geeks 4 Geeks Welcomes You
