How to get all values of a HashMap

In this article, we will discuss how to get all values of a HashMap or implementation classes of Map interface like LinkedHashMap or TreeMap

 

HashMap –> retrieves values, in random order of keys
LinkedHashMap –> retrieves values, as per insertion order of keys
TreeMap –> retrieves values, as per some sorting order of keys

 

Solution:

  • use values() method of Map interface
  • which returns Collection of values

 

Example: To get all values of a HashMap using values() method of Collection interface

Syntax:

Collection<String> values = hashMap.values();

 

GetAllValuesOfHashMap.java

package in.bench.resources.java.map;

import java.util.Collection;
import java.util.HashMap;

public class GetAllValuesOfHashMap {

	public static void main(String[] args) {

		// creating HashMap object of type <String, String>
		HashMap<String, String> hm = new HashMap<String, String>(); 

		// adding key-value pairs to HashMap object
		hm.put("Google", "Sundar Pichai");
		hm.put("Facebook", "Mark Zuckerberg");
		hm.put("LinkedIn", "Reid Hoffman");
		hm.put("Apple", "Steve Jobs");
		hm.put("Microsoft", "Bill Gates");

		System.out.println("all Key-Value pairs:\n\n" + hm + "\n\n");


		System.out.println("List of all values: \n");

		// Iterating value using values()
		Collection<String> founders = hm.values();
		for(String founder : founders) {
			System.out.println(founder);
		}
	}
}

Output:

all Key-Value pairs:

{Facebook=Mark Zuckerberg, Microsoft=Bill Gates, Google=Sundar Pichai, 
Apple=Steve Jobs, LinkedIn=Reid Hoffman}


List of all values: 

Mark Zuckerberg
Bill Gates
Sundar Pichai
Steve Jobs
Reid Hoffman

 

References:

https://docs.oracle.com/javase/tutorial/collections/intro/
https://docs.oracle.com/javase/tutorial/collections/interfaces/collection.html
https://docs.oracle.com/javase/7/docs/api/java/util/Collection.html
https://docs.oracle.com/javase/7/docs/api/java/util/Map.html
https://docs.oracle.com/javase/7/docs/api/java/util/Map.Entry.html
https://docs.oracle.com/javase/tutorial/collections/interfaces/map.html
https://docs.oracle.com/javase/7/docs/api/java/util/HashMap.html
https://docs.oracle.com/javase/8/docs/api/java/util/HashMap.html
https://docs.oracle.com/javase/tutorial/collections/interfaces/set.html
https://docs.oracle.com/javase/7/docs/api/java/util/Set.html
https://docs.oracle.com/javase/7/docs/api/java/util/Iterator.html
https://docs.oracle.com/javase/8/docs/api/java/util/Iterator.html
http://docs.oracle.com/javase/6/docs/api/java/util/LinkedHashMap.html
https://docs.oracle.com/javase/8/docs/api/java/util/LinkedHashMap.html
https://docs.oracle.com/javase/7/docs/api/java/util/TreeMap.html
https://docs.oracle.com/javase/8/docs/api/java/util/TreeMap.html

 

Happy Coding !!
Happy Learning !!

How to get all Entries or Key-Value pairs of HashMap
How to get all keys of a HashMap