Map containsValue() method in Java with Examples (original) (raw)

Last Updated : 31 Dec, 2018

The java.util.Map.containsValue() method is used to check whether a particular value is being mapped by a single or more than one key in the Map. It takes the value as a parameter and returns True if that value is mapped by any of the key in the map.Syntax:

boolean containsValue(Object Value)

Parameters: The method takes just one parameter Value of Object type and refers to the value whose mapping is supposed to be checked by any key inside the map.Return Value: The method returns boolean true if the mapping of the value is detected else false. Below programs illustrate the java.util.Map.containsValue() method:Program 1: Mapping String Values to Integer Keys.

Java `

// Java code to illustrate the containsValue() method

import java.util.*;

public class Map_Demo { public static void main(String[] args) { // Creating an empty Map Map<Integer, String> map = new HashMap<Integer, String>();

    // Mapping string values to int keys
    map.put(10, "Geeks");
    map.put(15, "4");
    map.put(20, "Geeks");
    map.put(25, "Welcomes");
    map.put(30, "You");

    // Displaying the Map
    System.out.println("Initial Mappings are: " + map);

    // Checking for the Value 'Geeks'
    System.out.println("Is the value 'Geeks' present? " + map.containsValue("Geeks"));

    // Checking for the Value 'World'
    System.out.println("Is the value 'World' present? " + map.containsValue("World"));
}

}

`

Output:

Initial Mappings are: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4} Is the value 'Geeks' present? true Is the value 'World' present? false

Program 2: Mapping Integer Values to String Keys.

Java `

// Java code to illustrate the containsValue() method

import java.util.*;

public class Map_Demo { public static void main(String[] args) { // Creating an empty Map Map<String, Integer> map = new HashMap<String, Integer>();

    // Mapping int values to string keys
    map.put("Geeks", 10);
    map.put("4", 15);
    map.put("Geeks", 20);
    map.put("Welcomes", 25);
    map.put("You", 30);

    // Displaying the Map
    System.out.println("Initial Mappings are: " + map);

    // Checking for the Value '10'
    System.out.println("Is the value '10' present? " + map.containsValue(10));

    // Checking for the Value '30'
    System.out.println("Is the value '30' present? " + map.containsValue(30));

    // Checking for the Value '40'
    System.out.println("Is the value '40' present? " + map.containsValue(40));
}

}

`

Output:

Initial Mappings are: {4=15, Geeks=20, You=30, Welcomes=25} Is the value '10' present? false Is the value '30' present? true Is the value '40' present? false

Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Map.html#containsValue(java.lang.Object)