How to check whether a particular value is present in HashMap ?

In this article, we will discuss how to check whether a value is present in the invoking HashMap or Not ?

1. Searching a value from HashMap :

  • Method signature : boolean containsValue(Object value)
  • This method is used to search specified value from invoking Map object;
  • it can be HashMap or LinkedHashMap or TreeMap
  • Returns true, if value is present;
  • otherwise return false
  • Note: Same example can be used to search for any particular value in LinkedHashMap and TreeMap

SearchSpecifiedValueFromHashMap.java

package in.bench.resources.java.map;

import java.util.HashMap;

public class SearchSpecifiedValueFromHashMap {

	public static void main(String[] args) {

		// creating HashMap object of type <String, String>
		HashMap<String, String> hashMap = new HashMap<String, String>();


		// adding key-value pairs to HashMap object
		hashMap.put("Google", "Sundar Pichai");
		hashMap.put("Facebook", "Mark Zuckerberg");
		hashMap.put("LinkedIn", "Reid Hoffman");
		hashMap.put("Apple", "Steve Jobs");
		hashMap.put("Microsoft", "Bill Gates");


		// printing all Key-Value pairs
		System.out.println("all Key-Value pairs:\n\n" + hashMap);


		// search for value
		boolean searchValue = hashMap.containsValue("Bill Gates");


		// print to console - searchValue
		System.out.println("\n\nWhether value 'Bill Gates' is present"
				+ " in hashMap ? "
				+ searchValue);


		// print to console
		System.out.println("\n\nWhether value 'Steve Jobs' is present"
				+ " in hashMap ? " 
				+ hashMap.containsValue("Steve Jobs"));


		// print to console
		System.out.println("\n\nWhether key 'Shiv Nadar' is present"
				+ " in hashMap ? " 
				+ hashMap.containsValue("Shiv Nadar"));
	}
}

Output:

all Key-Value pairs:

{Google=Sundar Pichai, LinkedIn=Reid Hoffman, Apple=Steve Jobs, 
Microsoft=Bill Gates, Facebook=Mark Zuckerberg}


Whether value 'Bill Gates' is present in hashMap ? true


Whether value 'Steve Jobs' is present in hashMap ? true


Whether key 'Shiv Nadar' is present in hashMap ? false

References:

Happy Coding !!
Happy Learning !!

Adding one HashMap to another HashMap using putAll method
How to check whether a particular key is present in HashMap ?