Programming Articles - Page 2900 of 3366

To check whether two HashMap are equal or not, use the equals() method.Let us first create the first HashMap −// Create hash map 1 HashMap hm1 = new HashMap(); hm1.put("Shirts", new Integer(700)); hm1.put("Trousers", new Integer(600)); hm1.put("Jeans", new Integer(1200)); hm1.put("Android TV", new Integer(450)); hm1.put("Air Purifiers", new Integer(300)); hm1.put("Food Processors", new Integer(950));Let us now create the second HashMap −HashMap hm2 = new HashMap(); hm2.put("Shirts", new Integer(700)); hm2.put("Trousers", new Integer(600)); hm2.put("Jeans", new Integer(1200)); hm2.put("Android TV", new Integer(450)); hm2.put("Air Purifiers", new Integer(300)); hm2.put("Food Processors", new Integer(950));To check whether both the HashMap are equal or not, use the equals() method like this −hm1.equals(hm2)The following is ... Read More

Use the clone() method to clone HashMap.The following is our HashMap with elements −HashMap hm1 = new HashMap(); hm1.put("Shirts", new Integer(700)); hm1.put("Trousers", new Integer(600)); hm1.put("Jeans", new Integer(1200)); hm1.put("Android TV", new Integer(450)); hm1.put("Air Purifiers", new Integer(300)); hm1.put("Food Processors", new Integer(950));Create another HashMap and clone the first HashMap into it −HashMap hm2 = (HashMap)hm1.clone();The following is an example to clone HashMap in Java −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create hash map HashMap hm1 = new HashMap(); ... Read More

Create a HashMap and add elements to it −HashMap hm = new HashMap(); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600)); hm.put("Backpack", new Integer(1200));The following is the code snippet to retrieve a set of Map.Entry elements −Set s = hm.entrySet(); Iterator iter = s.iterator(); System.out.println("Key\tValue"); while (iter.hasNext()) { Map.Entry e = (Map.Entry) iter.next(); System.out.println(e.getKey() + " " + e.getValue()); }The following is an example to retrieve a set of Map.Entry elements from a HashMap −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { ... Read More

First, create a HashMap and add elements −HashMap hm = new HashMap(); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600)); hm.put("Backpack", new Integer(1200));Now, retrieve all the values −Collection getValues = hm.values(); System.out.println("Values..."); Iterator i = getValues.iterator(); while (i.hasNext()) { System.out.println(i.next()); }The following is an example to get the set of all the values in the HashMap −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create hash map HashMap hm = new HashMap(); ... Read More

In Java, maps are a powerful and versatile way to store key-value pairs. Often, you may find the need to merge the contents of one map into another. This can be done effortlessly using the putAll method available in the Map interface. Let's explore this functionality with an example and a step-by-step explanation. Problem Statement The goal is to combine two maps by adding all entries or selectively adding entries without overwriting existing ones in the destination map. Input Map 1 (Destination Map) Wallet: 700 Belt: 600 Map 2 (Source Map)  Bag: 1100 Sunglasses: 2000 ... Read More

Use Iterator to iterate through the values of HashMap −HashMap hm = new HashMap(); // Put elements to the map hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Frames", new Integer(800)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Now, use Iterator to display each and every value and key −// Get an iterator Iterator i = set.iterator(); // Display elements while(i.hasNext()) { Map.Entry me = (Map.Entry)i.next(); System.out.print(me.getKey() + ": "); System.out.println(me.getValue()); }The following is an example to iterate through the values of HashMap −Example Live Demoimport java.util.*; public class Demo { public static ... Read More

Use the remove() method to remove a key only if it is associated with a given value.Let’s say the following is our HashMap −// Create a hash map HashMap hm = new HashMap(); // Put elements to the map hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Frames", new Integer(800)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Here, we are removing a key “Belt” only if it is associated with the given value 600 −hm.remove("Belt", 600);The following is an example to remove a key only if it is associated with a given value −Example Live Demoimport java.util.*; public class Demo {    public static void ... Read More

In this article, we will learn how to remove a specific key from a HashMap in Java. By doing this, we can dynamically update the contents of the map, which is helpful in many data manipulation scenarios. We will demonstrate two different approaches: one that uses the straightforward remove() method to delete a specific key, and another that leverages an iterator to find and remove the key based on a condition while iterating. Each approach allows us to efficiently manage data in HashMap based on different requirements. Problem Statement Given a HashMap with key-value pairs, write Java programs to ... Read More

First, create a HashMap and add elements to it −// Create a hash map HashMap hm = new HashMap(); // Put elements to the map hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Frames", new Integer(800)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Now, to modify the value associated with a given key, use the put() method. Here, we are modifying the value for the key “Frames” −hm.put("Frames", "900");The following is an example to modify the value associated with a given key −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { ... Read More

Use the get() method to get the value associated with a given key.Here is our HashMap and its elements −// Create a hash map HashMap hm = new HashMap(); // Put elements to the map hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Frames", new Integer(800)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));To get the associated value. the key is set as a parameter like this −hm.get("Frames")Above, the key is Frames and we are fetching the value associated with it.The following is an example to get the value associated with a given key in Java HashMap −Example Live Demoimport java.util.*; public class Demo { ... Read More