C# Interview Question #56

What is a lambda expression in C#?

Exceptions, Delegates, Events & Lambdas Mid-Level Intermediate

Quick Interview Answer

A lambda expression is a concise way to represent an anonymous function. Lambdas are commonly used with delegates, LINQ, events, and asynchronous APIs.

Detailed Explanation

A lambda expression is a concise way to represent an anonymous function. Lambdas are commonly used with delegates, LINQ, events, and asynchronous APIs.

The lambda operator is =>. Parameters appear on the left and the expression or statement body appears on the right.

Lambdas can capture variables from their surrounding scope, which creates a closure. Captures should be understood in performance-sensitive or long-lived code because they can affect allocations and object lifetimes.

Code Example

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

var active = products
    .Where(p => p.IsActive)
    .ToList();