Lambda expression syntax in C Sharp (C#) - Mini Project: Build & Apply

Lambda Expression Syntax in C#

📖 Scenario: You are working on a simple program that processes a list of numbers. You want to use a lambda expression to filter and transform these numbers easily.

🎯 Goal: Build a C# program that uses a lambda expression to select even numbers from a list and then doubles each selected number.

📋 What You'll Learn

Create a list of integers with specific values

Create a lambda expression to filter even numbers

Use the lambda expression to transform the filtered numbers by doubling them

Print the resulting list of doubled even numbers

💡 Why This Matters

🌍 Real World

Filtering and transforming lists of data is common in many programs, such as processing user inputs, handling collections of items, or working with data streams.

💼 Career

Understanding lambda expressions and list operations is essential for C# developers to write concise and readable code, especially when working with collections and LINQ.

1

Create the list of numbers

Create a list of integers called numbers with these exact values: 1, 2, 3, 4, 5, 6.

C Sharp (C#)

# Create the list of numbers
// Your code here

Need a hint?

Use List<int> and initialize it with the values inside curly braces.

2

Create a lambda expression to filter even numbers

Create a variable called evenNumbers that uses numbers.FindAll(n => n % 2 == 0) to select only even numbers from numbers.

C Sharp (C#)

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        List numbers = new List { 1, 2, 3, 4, 5, 6 };
        // Create evenNumbers using a lambda expression to filter even numbers
        // Your code here
    }
}

Need a hint?

Use FindAll method with a lambda expression n => n % 2 == 0 to get even numbers.

3

Double the filtered even numbers using a lambda expression

Create a variable called doubledEvenNumbers that uses evenNumbers.ConvertAll(n => n * 2) to double each number in evenNumbers.

C Sharp (C#)

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        List numbers = new List { 1, 2, 3, 4, 5, 6 };
        List evenNumbers = numbers.FindAll(n => n % 2 == 0);
        // Create doubledEvenNumbers by doubling each number in evenNumbers using a lambda
        // Your code here
    }
}

Need a hint?

Use ConvertAll with a lambda expression n => n * 2 to double each number.

4

Print the doubled even numbers

Use foreach to print each number in doubledEvenNumbers on its own line.

C Sharp (C#)

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        List numbers = new List { 1, 2, 3, 4, 5, 6 };
        List evenNumbers = numbers.FindAll(n => n % 2 == 0);
        List doubledEvenNumbers = evenNumbers.ConvertAll(n => n * 2);
        // Print each number in doubledEvenNumbers
        // Your code here
    }
}

Need a hint?

Use a foreach loop to print each number with Console.WriteLine.