Java Program To Remove Duplicate Elements From List
Chapter:
Miscellaneous
Last Updated:
07-10-2023 07:01:17 UTC
Program:
/* ............... START ............... */
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class RemoveDuplicatesFromList {
public static void main(String[] args) {
// Create a list with duplicate elements
List<Integer> listWithDuplicates = new ArrayList<>();
listWithDuplicates.add(1);
listWithDuplicates.add(2);
listWithDuplicates.add(3);
listWithDuplicates.add(2);
listWithDuplicates.add(4);
listWithDuplicates.add(1);
// Create a Set to store unique elements
Set<Integer> uniqueSet = new HashSet<>();
// Iterate through the original list and add elements to the set
// Duplicate elements will automatically be removed
for (Integer element : listWithDuplicates) {
uniqueSet.add(element);
}
// Create a new list to store the unique elements
List<Integer> listWithoutDuplicates = new ArrayList<>(uniqueSet);
// Print the list without duplicates
System.out.println("List with duplicates: " + listWithDuplicates);
System.out.println("List without duplicates: " + listWithoutDuplicates);
}
}
/* ............... END ............... */
Output
List with duplicates: [1, 2, 3, 2, 4, 1]
List without duplicates: [1, 2, 3, 4]
Notes:
-
First we create a list called listWithDuplicates containing some duplicate elements.
- In next step create a HashSet called uniqueSet to store the unique elements from the original list. The HashSet automatically removes duplicates because it doesn't allow duplicate elements.
- Then we iterate through the original list and add each element to the uniqueSet.
- Finally, we create a new list called listWithoutDuplicates and initialize it with the elements from the uniqueSet. This gives us a list without duplicate elements.
- When you run this program, you will see that the list listWithoutDuplicates contains the unique elements from the original list, and duplicates are removed.