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Dictionary remove() Method in Java

  • Last Updated : 11 Oct, 2018
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The remove() method of Dictionary Class accepts a key as a parameter and removes the corresponding value mapped to the key.

Syntax:

public abstract V remove(Object key)

Parameters: The function accepts a parameter key which denotes the key which is to be removed from the dictionary along with its mappings.

Return Values: The function returns the value which was mapped to the key or returns NULL if the key had no mapping.

Exception: The function throws no NullPointerException if the key passed as parameter is NULL.



Below programs illustrate the use of java.util.Dictionary.remove() method:

Program 1:




// Java Program to illustrate
// java.util.Dictionary.remove() method
  
import java.util.*;
  
class GFG {
    public static void main(String[] args)
    {
        // Create a new hashtable
        Dictionary<Integer, String>
            d = new Hashtable<Integer, String>();
  
        // Insert elements in the hashtable
        d.put(1, "Geeks");
        d.put(2, "for");
        d.put(3, "Geeks");
  
        // Print the Dictionary
        System.out.println("\nDictionary: " + d);
  
        // Display the removed value
        System.out.println(d.remove(3)
                           + " has been removed");
  
        // Print the Dictionary
        System.out.println("\nDictionary: " + d);
    }
}
Output:
Dictionary: {3=Geeks, 2=for, 1=Geeks}
Geeks has been removed

Dictionary: {2=for, 1=Geeks}

Program 2:




// Java Program to illustrate
// java.util.Dictionary.remove() method
  
import java.util.*;
  
class GFG {
    public static void main(String[] args)
    {
        // Create a new hashtable
        Dictionary<String, String> d = new Hashtable<String, String>();
  
        // Insert elements in the hashtable
        d.put("a", "GFG");
        d.put("b", "gfg");
  
        // Print the Dictionary
        System.out.println("\nDictionary: " + d);
  
        // Display the removed value
        System.out.println(d.remove("a")
                           + " has been removed");
        System.out.println(d.remove("b")
                           + " has been removed");
  
        // Print the Dictionary
        System.out.println("\nDictionary: " + d);
  
        // returns true
        if (d.isEmpty()) {
            System.out.println("Dictionary "
                               + "is empty");
        }
        else
            System.out.println("Dictionary "
                               + "is not empty");
    }
}
Output:
Dictionary: {b=gfg, a=GFG}
GFG has been removed
gfg has been removed

Dictionary: {}
Dictionary is empty

Reference:https://docs.oracle.com/javase/7/docs/api/java/util/Dictionary.html#remove()

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