Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

How to Add Key-Value pairs to LinkedHashMap in Java?

  • Last Updated : 22 Dec, 2020

LinkedHashMap is a Hash table and linked list implementation of the Map interface. In LinkedHashMap order of key-value pair depends on the order in which keys were inserted into the map. Insertion order does not affect if a key is reinserted into the map.

Example:

Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

Input: 
     Key: 1
     Value : 1221
     Key: 2
     Value : 2112
Output:
    Keys : [1,2]
    Values : [1221,2112]
    Key-Value pairs : [1=1221, 2=2112]

Methods Use:

  1. put(Key, Value): First parameter as key and second parameter as Value.
  2. keySet(): Creates a set out of the key elements contained in the hash map.
  3. values(): Create a set out of the values in the hash map.

Approach:



  1. Create two-variable named as Key and Value
  2. Accept the input from user in Key and in Value
  3. Use put() method to add Key-Value pair inside the LinkedHashMap

Below is the implementation of the above approach:

Java




// Java Program to add key-value 
// pairs to LinkedHashMap
import java.util.*;
public class Main {
    
    public static void main(String[] args)
    {
        // create an instance of LinkedHashMap
        LinkedHashMap<Integer, Integer> map
            = new LinkedHashMap<Integer, Integer>();
  
        int num, key, val;
        num = 2;
        for (int i = 0; i < num; i++) {
            
            // Taking inputs from user
            key = i + 1;
            val = key * 10;
  
            // Add mappings using put method
            map.put(key, val);
        }
        // Displaying key
        System.out.println("Keys: " + map.keySet());
  
        // Displaying value
        System.out.println("Values: " + map.values());
  
        // Displaying key-value pair
        System.out.println("Key-Value pairs: "
                           + map.entrySet());
    }
}
Output
Keys: [1, 2]
Values: [10, 20]
Key-Value pairs: [1=10, 2=20]

Time Complexity: O(1)




My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!