Programming Articles - Page 2902 of 3366

In this article, we will learn to get the size of an ArrayList in Java. In Java, an ArrayList is a resizable array implementation of the List interface. Unlike arrays, which have a fixed length, an ArrayList dynamically grows as elements are added. Using the size() Method The size of an ArrayList can be obtained by using the java.util.ArrayList.size() method as it returns the number of elements in the ArrayList i.e. the size. Syntax int size = arrayList.size(); Getting the Size of an ArrayList  Following are the steps to get the size of an ArrayList using the size() method − ... Read More

At first, create the first HashSet and add elements to it −// create hash set 1 HashSet hs1 = new HashSet(); hs1.add("G"); hs1.add("H"); hs1.add("I"); hs1.add("J"); hs1.add("K");Create the second HashSet and add elements to it −// create hash set 2 HashSet hs2 = new HashSet(); hs2.add("G"); hs2.add("H"); hs2.add("I"); hs2.add("J"); hs2.add("K");To check whether both the HashSet are equal or not, use the equals() method −hs1.equals(hs2)The following is an example to check whether two HashSet are equal −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // create hash set ... Read More

First, create a HashSet and elements to it −HashSet hs = new HashSet(); // add elements to the hash set hs.add("B"); hs.add("A"); hs.add("D"); hs.add("E"); hs.add("C"); hs.add("F"); hs.add("K");Let us now convert the above HashSet to an array −Object[] ob = hs.toArray();The following is an example to convert elements in a HashSet to an array −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // create a hash set HashSet hs = new HashSet(); // add elements ... Read More

To check whether a HashSet is empty or not, use the isEmpty() method.Create a HashSet −HashSet hs = new HashSet();Add elements to the HashSet −hs.add("B"); hs.add("A"); hs.add("D"); hs.add("E"); hs.add("C"); hs.add("F"); hs.add("K"); hs.add("M"); hs.add("N");Now, check whether the HashSet is empty or not. Since we added elements above, it won’t be empty −hs.isEmpty();The following is an example that checks whether a HashSet is empty or not −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // create a hash set HashSet hs = ... Read More

Use the size() method to get the size of HashMap. Let us first create a HashMapHashMap hm = new HashMap();Now, add some elements −hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Franes", new Integer(800)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Since, we added 5 elements above, therefore, the size() method will give 5 as the result −set.size()The following is an example to find the size of HashMap −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = ... Read More

Elements can be filled in a Java float array in a specified range using the java.util.Arrays.fill() method. This method assigns the required float value in the specified range to the float array in Java.The parameters required for the Arrays.fill() method are the array name, the index of the first element to be filled(inclusive), the index of the last element to be filled(exclusive) and the value that is to be stored in the array elements.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Arrays; public class Demo { public static void main(String[] argv) throws Exception { ... Read More

Elements can be filled in a Java byte array in a specified range using the java.util.Arrays.fill() method. This method assigns the required byte value in the specified range to the byte array in Java.The parameters required for the Arrays.fill() method are the array name, the index of the first element to be filled(inclusive), the index of the last element to be filled(exclusive) and the value that is to be stored in the array elements.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Arrays; public class Demo { public static void main(String[] argv) throws Exception { ... Read More

Use the isEmpty() method to check of a HashMap is empty or not. Let us first create the HashMap −HashMap hm = new HashMap();Now, add some elements −hm.put("Bag", new Integer(1100)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Since, we added elements above, therefore, the HashMap isn’t empty. Let us check −set.isEmpty()The following is an example to check if a HashMap is empty or not −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = new HashMap(); ... Read More

In this article, we will write a Java program to create a HashMap and add key-value pairs. We will be using the HashMap class we can import HashMap class form java.util package. A HashMap is a collection that stores data in the form of key-value pairs, allowing quick retrieval of values based on their keys. We'll also see how to display the elements stored in the HashMap using an iterator in our given program. Problem Statement Write a program in Java to create a HashMap and add key-value pairs − Output Belt: 600Wallet: 700Bag: 1100 Steps to create a HashMap and add ... Read More

Create a HashMap −HashMap hm = new HashMap();Add elements to the HashMap that we will be displaying afterward −hm.put("Maths", new Integer(98)); hm.put("Science", new Integer(90)); hm.put("English", new Integer(97)); hm.put("Physics", new Integer(91));Now, to display the HashMap elements, use Iterator. The following is an example to display HashMap elements −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = new HashMap(); // Put elements to the map ... Read More