Remove duplicates from list of integers using Lambda expression in Java

Last update on April 28 2025 07:58:32 (UTC/GMT +8 hours)

Remove Duplicates from List of Integers

Write a Java program to implement a lambda expression to remove duplicates from a list of integers.

Sample Solution:

Java Code:

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        // Create a list of integers with duplicates
        List<Integer> nums = Arrays.asList(1, 2, 3, 3, 4, 3, 2, 5, 6, 1, 7, 7, 8, 10);
        // Print the list
        System.out.println("List elements " + nums);     
        // Remove duplicates using lambda expression
        List<Integer> unique_nums = new ArrayList<>();
        nums.stream()
                .distinct()
                .forEach(unique_nums::add);

        // Print the list without duplicates
        System.out.println("\nList elements without duplicates: " + unique_nums);
    }
}

Sample Output:

List elements [1, 2, 3, 3, 4, 3, 2, 5, 6, 1, 7, 7, 8, 10]

List elements without duplicates: [1, 2, 3, 4, 5, 6, 7, 8, 10]

Explanation:

In the above exercise we use the stream() method on the nums list to convert it into a stream. We call the distinct() method to filter out duplicate elements. The distinct() method ensures that only distinct elements are retained in the stream.

Finally, we use the forEach() method and a lambda expression unique_nums::add to add each unique element to the unique_nums list.

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to implement a lambda expression that removes duplicates and then sorts the resulting list in ascending order.
• Write a Java program to create a lambda that filters out duplicate integers and then computes the sum of the unique values.
• Write a Java program to implement a lambda that removes duplicates from a list of integers and returns the count of unique elements.
• Write a Java program to use a lambda expression with a distinct() operation to remove duplicates and then convert the list to a set.

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