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Java: Get a set view of the keys contained in this map


11. Get Set of Keys from Map

Write a Java program to get a set view of the keys contained in this map.

Sample Solution:-

Java Code:

import java.util.*;  
public class Example11 {  
     public static void main(String args[]){  
 
  HashMap<Integer,String> hash_map= new HashMap<Integer,String>();  
  
  hash_map.put(1,"Red");
  hash_map.put(2,"Green");
  hash_map.put(3,"Black");
  hash_map.put(4,"White");
  hash_map.put(5,"Blue");
  
  // get keyset value from map
   Set keyset = hash_map.keySet();
      
  // check key set values
   System.out.println("Key set values are: " + keyset);  
 }
}

Sample Output:

Key set values are: [1, 2, 3, 4, 5]

For more Practice: Solve these Related Problems:

  • Write a Java program to retrieve the key set from a HashMap using keySet() and then print all keys.
  • Write a Java program to convert a map’s key set to a list and then sort the keys in reverse order.
  • Write a Java program to use Java streams to filter a map’s keys based on a predicate and print the result.
  • Write a Java program to iterate over a map’s key set and count how many keys start with a specific letter.

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