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Iterate Hashmap In Java

Last Updated : Mar 11, 2024

Iterate Hashmap In Java

In this article we will show you the solution of iterate hashmap in java, Java allows you a number of different ways to iterate a Map. Keep in mind that since the Map interface is not a component of Collection, we cannot simply iterate across maps using iterators.

Java provides the Map interface for all maps. Even though a map is not a collection, it is still seen as a collection.

Since a Map does not extend the Collections interface, it is a separate interface.

We will now discuss the idea of how to iterate hashmap in java with an example.

Step By Step Guide On Iterate Hashmap In Java :-

Code 1

import java.util.Map;
import java.util.HashMap;
class TalkersCode
public static void main(String[] arg)
Map<String,String> map = new HashMap<String,String>();
map.put("Capgemini", "$500 billion");
map.put("Cognizant", "$30.5 billion");
map.forEach((k,v) -> System.out.println("Company: "+ k + ", Net worth: " + v));

Code 2

import java.util.*;
class talkerscodeIteration
public static void main(String[] arg)
Map<String, String> map = new HashMap<String, String>();
map.put("Amruta", "Shahane");
map.put("Harry", "Potter");
map.put("Ron", "Weasley");
for (String name: map.keySet()) //iteration over keys
//returns the value to which specified key is mapped
String lastname=map.get(firstname);
System.out.println("Key: " + name + ", Value: " + lastname);
  1. The "Map" and "HashMap" classes from the "java.util" package are imported in the first line of code.
  2. The "TalkersCode" class is developed.
  3. The main technique is developed.
  4. The "map" variable is given a fresh instance of the HashMap class. The data type "Map" is supplied to denote that the map's keys and values are both Strings.
  5. Using the put() method, two key-value pairs are added to the map. "Capgemini" is the first key, while "$500 billion" is the associated value. The value for the second key, "Cognizant," is "$30.5 billion."
  6. The "map" object receives a call to the forEach() method. Two parameters, k and v, which stand for the key and value of each entry in the map, are supplied as arguments to the lambda expression.
  7. The company name (stored in "k") and its associated net worth (stored in "v") are concatenated into a string using the lambda expression. This code prints its results to the console.

Conclusion :-

As a result, we have successfully learned how to iterate hashmap in java with an example.

Hash maps are used when it is necessary to store data as key-value pairs so that each element's value may be retrieved using its corresponding key.

I hope this article on iterate hashmap in java helps you and the steps and method mentioned above are easy to follow and implement.

Author Image About Ashish

Ashish is a dynamic and motivated individual with a passion of programming and an experienced programmer having 3+ years of experience in various languages like Java, Python, HTML, CSS, JavaScript, jQuery and various frameworks like Bootstrap

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