Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Check if a given key exists in Java HashMap
Use the containsKey() method and check if a given key exists in the HashMap or not.
Let us first create HashMap and add some 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));Now, let’s say we need to check whether the key “Bag” exists or not, For that, use the containsKey() method like this −
hm.containsKey("Bag")The following is an example to check if a given key exists in HashMap −
Example
import java.util.*;
public class Demo {
public static void main(String args[]) {
// 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));
// Get a set of the entries
Set set = hm.entrySet();
System.out.println("Elements in HashMap...");
// 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());
}
System.out.println();
System.out.println("Does Bag exist in the HashMap = "+hm.containsKey("Bag"));
}
}Output
Elements in HashMap... Frames: 800 Belt: 600 Wallet: 700 Bag: 1100 Sunglasses: 2000 Does Bag exist in the HashMap = true
Updated on: 30-Jul-2019
8K+ Views
Advertisements