Hashtable containsKey() Method in Java
Last Updated :
28 Jun, 2018
The java.util.Hashtable.containsKey() method is used to check whether a particular key is present in the Hashtable or not. It takes the key element as a parameter and returns True if that element is present in the table.
Syntax:
Hash_table.containsKey(key_element)
Parameters: The method takes just one parameter key_element which refers to the key whose presence is supposed to be checked inside a Hashtable.
Return Value: The method returns boolean true if the key is present in the Hashtable otherwise it returns false.
Below programs are used to illustrate the working of java.util.Hashtable.containsKey() Method:
Program 1:
import java.util.*;
public class Hash_Table_Demo {
public static void main(String[] args)
{
Hashtable<Integer, String> hash_table =
new Hashtable<Integer, String>();
hash_table.put( 10 , "Geeks" );
hash_table.put( 15 , "4" );
hash_table.put( 20 , "Geeks" );
hash_table.put( 25 , "Welcomes" );
hash_table.put( 30 , "You" );
System.out.println( "Initial Table is: " + hash_table);
System.out.println( "Is the key '20' present? " +
hash_table.containsKey( 20 ));
System.out.println( "Is the key '5' present? " +
hash_table.containsKey( 5 ));
}
}
|
Output:
Initial Table is: {10=Geeks, 20=Geeks, 30=You, 15=4, 25=Welcomes}
Is the key '20' present? true
Is the key '5' present? false
Program 2:
import java.util.*;
public class Hash_Table_Demo {
public static void main(String[] args)
{
Hashtable<String, Integer> hash_table=
new Hashtable<String, Integer>();
hash_table.put( "Geeks" , 10 );
hash_table.put( "4" , 15 );
hash_table.put( "Geeks" , 20 );
hash_table.put( "Welcomes" , 25 );
hash_table.put( "You" , 30 );
System.out.println( "Initial Table is: " + hash_table);
System.out.println( "Is the key 'Welcomes' present? " +
hash_table.containsKey( "Welcomes" ));
System.out.println( "Is the key 'World' present? " +
hash_table.containsKey( "World" ));
}
}
|
Output:
Initial Table is: {You=30, Welcomes=25, 4=15, Geeks=20}
Is the key 'Welcomes' present? true
Is the key 'World' present? false
Note: The same operation can be performed with any type of variation and combination of different data types.
Like Article
Suggest improvement
Share your thoughts in the comments
Please Login to comment...