Lambda Expressions
Contents
What is a Lambda Expression?
A lambda expression is an anonymous function and it is mostly used to create delegates in LINQ. Simply put, it's a method without a declaration, i.e., access modifier, return value declaration, and name.
Why do we need lambda expressions? (Why would we need to write a method without a name?)
Convenience. It's a shorthand that allows you to write a method in the same place you are going to use it. Especially useful in places where a method is being used only once, and the method definition is short. It saves you the effort of declaring and writing a separate method to the containing class.
Benefits:
- Reduced typing. No need to specify the name of the function, its return type, and its access modifier.
- When reading the code you don't need to look elsewhere for the method's definition.
Lambda expressions should be short. A complex definition makes the calling code difficult to read.
How do we define a lambda expression?
Lambda basic definition: Parameters => Executed code.
Simple example
n => n % 2 == 1
n is the input parameter n % 2 == 1 is the expression You can read n => n % 2 == 1 like: "input parameter named n goes to anonymous function which returns true if the input is odd".
Same example (now execute the lambda):
List<int> numbers = new List<int>{11,37,52};
List<int> oddNumbers = numbers.where(n => n % 2 == 1).ToList();
//Now oddNumbers is equal to 11 and 37
