Dictionary keys() Method in Java with Examples
Last Updated :
27 Dec, 2018
The keys() method of Dictionary class in Java is used to get the enumeration of the keys present in the dictionary.
Syntax:
Enumeration enu = DICTIONARY.keys()
Parameters: The method does not take any parameters.
Return value: The method returns an enumeration of the keys of the Dictionary.
Below programs are used to illustrate the working of the java.util.Dictionary.keys() method:
Program 1:
import java.util.*;
public class Dictionary_Demo {
public static void main(String[] args)
{
Dictionary<Integer, String> dict
= new Hashtable<Integer, String>();
dict.put( 10 , "Geeks" );
dict.put( 15 , "4" );
dict.put( 20 , "Geeks" );
dict.put( 25 , "Welcomes" );
dict.put( 30 , "You" );
System.out.println( "The Dictionary is: " + dict);
Enumeration enu = dict.keys();
System.out.println( "The enumeration of keys are:" );
while (enu.hasMoreElements()) {
System.out.println(enu.nextElement());
}
}
}
|
Output:
The Dictionary is: {10=Geeks, 20=Geeks, 30=You, 15=4, 25=Welcomes}
The enumeration of keys are:
10
20
30
15
25
Program 2:
import java.util.*;
public class Dictionary_Demo {
public static void main(String[] args)
{
Dictionary<String, Integer> dict
= new Hashtable<String, Integer>();
dict.put( "Geeks" , 10 );
dict.put( "4" , 15 );
dict.put( "Geeks" , 20 );
dict.put( "Welcomes" , 25 );
dict.put( "You" , 30 );
System.out.println( "The Dictionary is: " + dict);
Enumeration enu = dict.keys();
System.out.println( "The enumeration of keys are:" );
while (enu.hasMoreElements()) {
System.out.println(enu.nextElement());
}
}
}
|
Output:
The Dictionary is: {You=30, Welcomes=25, 4=15, Geeks=20}
The enumeration of keys are:
You
Welcomes
4
Geeks
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