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Retrieve All Keys and Values in HashMap in Java
To retrieve the set of keys from HashMap, use the keyset() method. However, for set of values, use the values() method.
Create a HashMap −
HashMap hm = new HashMap(); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600)); hm.put("Backpack", new Integer(1200));
Now, retrieve the keys −
Set keys = hm.keySet(); Iterator i = keys.iterator(); while (i.hasNext()) { System.out.println(i.next()); }
Retrieve the values −
Collection getValues = hm.values(); i = getValues.iterator(); while (i.hasNext()) { System.out.println(i.next()); }
The following is an example to get the set of all keys and values in HashMap −
Example
import java.util.*; public class Demo { public static void main(String args[]) { // Create hash map HashMap hm = new HashMap(); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600)); hm.put("Backpack", new Integer(1200)); System.out.println("Map = "+hm); System.out.println("\nKeys..."); Set keys = hm.keySet(); Iterator i = keys.iterator(); while (i.hasNext()) { System.out.println(i.next()); } System.out.println("\nValues..."); Collection getValues = hm.values(); i = getValues.iterator(); while (i.hasNext()) { System.out.println(i.next()); } } }
Output
Map = {Backpack=1200, Belt=600, Wallet=700} Keys... Backpack Belt Wallet Values... 1200 600 700
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