LINQ Interview Question #13

What are LINQ extension methods?

LINQ Fundamentals, Syntax, IEnumerable & IQueryable Junior Beginner

Quick Interview Answer

LINQ operators such as Where, Select, OrderBy, and Any are implemented as extension methods. Extension methods allow static methods to be called with instance-method syntax when the target type is compatible with the method's first parameter.

Detailed Explanation

The Enumerable class contains LINQ-to-Objects operators, while Queryable contains operators designed for IQueryable<T> expression trees.

Code Example

var result = numbers.Where(n => n > 5);

// Conceptually equivalent to:
var sameResult =
    Enumerable.Where(numbers, n => n > 5);