Lambda Expression

• It is an anonymous method which has no access modifier, no name and  no return statement. 

(input-parameters) => expression

• We can write lambda expression to achieve something with less code. Below example shows how we can write a code to get multiplication of two numbers with lambda expression and without lambda expression. 

    class Program
    {
        static void Main(string[] args)
        {
            //args => expression

            //Without Lambda Expression
            Console.WriteLine(Square(5));

            //With Lambda Expression and Func
            Func<int, int> multiplication = number => number * number;
            Console.WriteLine(multiplication(5));

            Console.Read();
        }
		
	private static int Square(int x)
        {
            return x * x;
        }
    }
	

• We can also use lambda expressions when we write LINQ in C#.

int[] numbers = { 2, 3, 4, 5 };
var squaredNumbers = numbers.Select(x => x * x);
Console.WriteLine(string.Join(" ", squaredNumbers));
// Output:
// 4 9 16 25

//Consider new BookRepository().GetBooks() returns list of books
var listofBooks = new BookRepository().GetBooks();
List<Books> cheapBooks = listofBooks.FindAll(b => b.price < 20).ToList();