C# Lambda Function

C# Lambda functions are a valuable feature that allows for brief and efficient coding syntax using lambda expressions. They provide a shorthand way to create anonymous functions that can be used as arguments for other functions or as standalone functions.


  1. C# Lambda Function is a valuable feature as it provides a short and efficient syntax to write code using lambda expressions.
  2. C# Lambda Functions have multiple use cases such as filtering and sorting data, defining delegates, and handling events.
  3. Whether you're working synchronously or asynchronously C# Lambda functions can be used effectively.
  4. Lambda functions are short and readable but with limited features as compared to traditional C# methods which are more powerful and flexible but with longer code.
  5. By combining Lambda functions with other C# features like LINQ, we can create powerful and efficient solutions.

Here we will explore the basics of C# lambda function, including their syntax and advantages.

We can define a Lambda function without explicitly declaring a separate named method. Lambda functions can be used in various contexts, such as filtering and sorting data, defining delegates, and handling events.

Lambda functions in C# use lambda operator => to separate the input parameters from the function body. For example, the following code snippet creates a lambda function that takes two integers and returns:

Func<int, int, int> sum = (x, y) => x + y;

Here, the lambda function takes two integer parameters (x, y) and returns their sum (x + y). The Func delegate specifies the types of input parameters and the return value.

There are many advantages of using lambda functions C#. They can help to reduce code complexity, increase readability, and improve code efficiency and also they enable developers to write functional programming style code in C#, which can simplify and enhance the codebase.

How to Run a Lambda Function in C#?

We can use delegate types such as Func and Action to write Lambda functions. Func is a generic delegate type that represents a function with one or more input parameters and a return value while Action is a similar delegate type that represents a function with one or more input parameters and no return value.

We can assign it to a delegate variable or pass it to a method as a parameter.

Func<int, bool> isEven = x => x % 2 == 0;

bool result = isEven(4); // returns true

Lambda Functions vs. LINQ

In general, lambda functions are best suited for simple operations on small data sets where we need to define inline functions, while LINQ is more appropriate for complex operations on larger data sets. LINQ also uses Lambda functions for conditions like filtering and sorting. For example, if you need to filter a small collection of integers, a lambda expression might be the simplest approach. We use Lambda expressions to write the body of Lambda functions, here is a simple example of an expression:

var numbers = new List<int> { 1, 2, 3, 4, 5 };
var evens = numbers.Where(x => x % 2 == 0);

Here, the lambda expression is used with the Where operator to filter the numbers list and return only the even numbers.

And if you need to perform a complex query on a large data set, LINQ might be the better choice. Here"s an example of using LINQ to group and count the words in a large text file:

var words = File.ReadAllText("text.txt").Split();
var groups = from word in words
             group word by word into g
             select new { Word = g.Key, Count = g.Count() };

In this example, the LINQ query groups the words by their value and counts how many times each word appears in the file.

In summary, both lambda functions and LINQ are powerful tools for working with data in C#. Which one you choose to use depends on the specific task at hand. C# inline Lambda function feature makes life easy!

Why Use Lambda Functions in C#?

Lambda functions offer several benefits, one of the most significant advantages is that they simplify code by allowing developers to write shorter expressions. This, in turn, can improve performance, as less code often means less overhead.

Another benefit is that they can make code more readable. For example, a long chain of method calls and conditions can be replaced with a single lambda expression, and invoke lambda function.

Common use cases for C# lambda functions include filtering and sorting data, performing calculations on collections, and defining event handlers.

Lambda Functions vs. Methods

Lambda functions and traditional methods both have their advantages and limitations. Lambda functions are short and can be more readable in certain scenarios, but they can also be limited in their functionality compared to traditional methods.

Traditional methods offer more flexibility and control over the code, allowing for more complex logic and branching. However, this often comes at the cost of longer, more verbose code.

Overall, the choice between lambda functions and traditional methods in C# depends on the specific use case and the preferences of the developer. It is important to consider the benefits and limitations of both approaches before deciding which to use in a particular scenario.

Can a Lambda Function be a Variable?

Yes, a lambda function can be assigned to a variable of a delegate type. For example:

Func<int, int> square = num => num * num;

This assigns a lambda function to a variable named "square" of type Func<int, int>. This lambda function takes an integer parameter named "num" and returns the square of "num".

Asynchronous Lambda Functions

Lambda functions can be used with both synchronous and asynchronous manner.

Let’s have an example for Async Lambda function C#:

Func<int, int, Task<int>> AddAsync = async (x, y) =>
    await Task.Delay(1000);
    return x + y;
int result = await AddAsync(3, 5);

We have created a lambda function named “AddAsync”, which is asynchronous. It takes two integers as input parameters and returns their sum as a "Task<int>". The function utilizes the "async" and "await" keywords to define an asynchronous operation that simulates a delay of 1 second before returning the sum.

When calling an asynchronous lambda function like "AddAsync", the "await" keyword is used to invoke the function asynchronously and receive its output when it"s available. It should be noted that asynchronous lambda functions need to return a "Task" or "Task<T>" object, and their function body must include asynchronous operations that return "Task" or "Task<T>" objects.

C# Local Function vs. Lambda

Local functions were introduced in C# 7.0 and are a way to define a method inside another method. Local functions and lambda functions serve different purposes. Local functions are used when a method needs to be reused within the same method, while lambda functions are used for short, one-time use cases or when we need to pass a small piece of code to another function or method.

Summary : Lambda functions C#

In summary, Lambda functions in C# provide a powerful and efficient way to write code, resulting in saved time and effort. In his article we explored different aspects of lambda functions, such as their creation, execution, and advantages compared to traditional methods. Additionally, we discussed how they differ from LINQ and the various scenarios in which they can be used, as well as Lambda functions with local functions.

Furthermore, we also have covered the concepts of synchronous and asynchronous lambda functions and how developing proficiency in lambda functions can improve code effectiveness, streamline complex coding tasks, and contribute to an enhanced programming experience overall.

You can read more about Lambda expressions, Lambda with LINQ and List with Lambda expression in the website.