What are Lambda Expressions in C#
What are Lambda Expressions in C#, and why do they matter? Lambda expressions in C# are a powerful and versatile feature that allows developers to create anonymous functions concisely and expressively.
They are widely used in C# programming to simplify complex tasks, improve code readability, and increase the overall efficiency of the code. If you want to skyrocket your C# career, check out our powerful ASP.NET full-stack web development course that also covers test-driven development and C# software architecture.
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What is a Lambda Expression?
A lambda expression is a small piece of code that can be passed as an argument to a method or used to define a delegate. It consists of two parts: the parameters and the expression. The parameters represent the input to the lambda expression, and the expression represents the logic that should be executed when the lambda expression is invoked.
The Syntax
The syntax of a lambda expression is simple and easy to understand. It starts with the keyword “lambda” followed by the parameters, the => operator and the expression. For example, a lambda expression that takes two parameters and returns their sum can be written as (x,y) => x + y.
With vs. Without Lambda Expression
One of the key advantages of lambda expressions is that they allow developers to write code that is more expressive and easy to understand. They can be used to replace complex loops, if-else statements and other imperative code with a simple, functional syntax.
For example, a common task in C# programming is sorting a list of objects. Without lambda expressions, this could be done using the Array.Sort() method and a custom comparer.
Imagine a list of people:
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class Person { public string Name { get; set; } public int Age { get; set; } } List<Person> people = new List<Person> { new Person { Name = "John", Age = 25 }, new Person { Name = "Mary", Age = 32 }, new Person { Name = "Bob", Age = 19 } }; |
And this is how we can sort them using the Array.Sort() method:
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people.Sort(delegate (Person x, Person y) { return x.Age.CompareTo(y.Age); }); |
With lambda expressions, we can write the above code more expressively by using the OrderBy extension method.
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people = people.OrderBy(p => p.Age); |
It’s more readable and easy to understand the intent of the code. Another advantage of lambda expressions is that they can be used to create delegates and event handlers more conveniently. With lambda expressions, developers can skip creating separate methods for these purposes without adding complexity.
Use Cases
There are many use cases for lambda expressions in C#; some of the most common ones include:
- Delegates and Event Handlers: Lambda expressions can be used to create delegates and event handlers more efficiently and conveniently. With lambda expressions, developers can avoid creating separate methods for these purposes, which can simplify the code and reduce the amount of boilerplate code that needs to be written.
- LINQ Queries: Lambda expressions are heavily used in LINQ, a set of extension methods that allow developers to perform queries on any data source that implements the IEnumerable or IQueryable interface. For example, developers can use lambda expressions to filter and sort data, group data, or perform other operations on collections, arrays, and lists.
- Functional Programming: Lambda expressions can be used to create functional programming constructs such as higher-order functions, closures, and currying. This can make the code more expressive and easy to understand and can also improve the overall efficiency of the code.
- Asynchronous Programming: Lambda expressions can be used to create asynchronous methods and event handlers. This can help improve the code’s performance and responsiveness and make it easier to work with async and await keywords.
- Data Validation and Sanitation: Lambda expressions can be used to write self-documented code to validate and sanitize data input, for example, to ensure that a string is not empty or that a number is within a certain range.
- Building Dynamic Queries: Lambda expressions can be used to build dynamic queries that can be executed against a data source. This allows developers to write more flexible queries and adapt to changing requirements.
- Array and List Manipulation: Lambda expressions can be used to filter, sort, and manipulate arrays and lists more efficiently and expressively. For example, developers can use lambda expressions to find the maximum or minimum value in a list or group items by certain criteria.
These are just a few examples of the many use cases for lambda expressions in C#. The versatility of lambda expressions makes them a valuable tool for any C# developer looking to improve their code quality and productivity. By the way, did you know that we offer a unique and powerful online course that boosts your C# career? Check it out here!
If you want to learn about sharing the catch block for possible exceptions that a try block may cause, read my article about catching multiple exceptions in C#.
Conclusion
In conclusion, lambda expressions in C# are a powerful and versatile feature that can help developers write more expressive, easier-to-understand code. They are widely used in C# programming and are an essential tool for any C# developer looking to improve their code quality and productivity.
I want to now how can i use sum lambda expression to calculated with sql server table
You must be able to use something like the following example
dbContext.People.Sum(person => person.Age);Comments are closed.