Filter even and odd numbers from list using Lambda expression in Java

Java Lambda Program: Exercise-4 with Solution

Write a Java program to implement a lambda expression to filter out even and odd numbers from a list of integers.

Sample Solution:

Java Code:

// Main.java
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class Main {
    public static void main(String[] args) {
        // Create a list of integers
        List nums = Arrays.asList(11, 23, 98, 34, 15, 32, 42, 80, 99, 100);
        
		// Print the original numbers
        System.out.println("Original numbers:");
        for (int n : nums) {
            System.out.print(n+ " ");
        }		

        // Filter out even numbers using lambda expression
        List evenNumbers = nums.stream()
                .filter(n -> n % 2 == 0)
                .collect(Collectors.toList());

        // Print the even numbers
        System.out.print("\nEven numbers:");
        for (int num : evenNumbers) {
            System.out.print(num + " ");
        }

        // Filter out odd numbers using lambda expression
        List oddNumbers = nums.stream()
                .filter(num -> num % 2 != 0)
                .collect(Collectors.toList());

        // Print the odd numbers
        System.out.print("\nOdd numbers:");
        for (int num : oddNumbers) {
            System.out.print(num + " ");
        }
    }
}

Sample Output:

Original numbers:
11 23 98 34 15 32 42 80 99 100
Even numbers:98 34 32 42 80 100
Odd numbers:11 23 15 99

Explanation:

At first create a list of integers called nums using the Arrays.asList() method and print the original list.

To filter out even numbers, we use the stream() method on the list nums to convert it into a stream. Now apply a lambda expression with the filter() method. The lambda expression (n -> n % 2 == 0) checks if a number is divisible by 2 (i.e., even). We collect the filtered even numbers into a new list using the collect() method with Collectors.toList().

To filter out odd numbers, we use a similar approach. We again use the stream() method on the nums list, apply a lambda expression (num -> num % 2 != 0) to check if a number is not divisible by 2 (i.e., odd), and collect the filtered odd numbers into a new list using collect() and Collectors.toList().

Flowchart:

Live Demo:

Java Code Editor:

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