F# Interview Questions and Answers for 10 years experience

1. What are the key differences between F# and C#?

   • Answer: F# is a functional-first language emphasizing immutability, pattern matching, and type inference, while C# is a multi-paradigm language primarily object-oriented. F# excels in data analysis and concurrency, while C# is widely used for general-purpose programming and larger applications. F#'s type system is more expressive, supporting features like discriminated unions and type providers. C# offers better interoperability with existing .NET libraries.

2. Explain immutability in F#. What are its benefits and drawbacks?

   • Answer: Immutability means that once a value is assigned, it cannot be changed. In F#, this is enforced by default. Benefits include simpler reasoning about code (no side effects), easier concurrency (no race conditions), and better suitability for functional programming paradigms. Drawbacks can be performance overhead in some cases (requiring new objects instead of modifying existing ones) and a steeper learning curve for programmers accustomed to mutable state.

3. Describe different ways to handle errors in F#.

   • Answer: F# primarily uses the `Result` type to handle potential errors. A `Result<'TSuccess, 'TError>` represents either a successful result (`Ok value`) or an error (`Error error`). Exceptions are used less frequently, generally reserved for truly exceptional circumstances. Other techniques include option types (`option<'T>`) to represent values that may be absent and pattern matching to gracefully handle various outcomes.

4. Explain the concept of discriminated unions in F#. Give an example.

   • Answer: Discriminated unions (DUs) allow defining a type that can be one of several named cases, each potentially with its own data. This is analogous to enums in other languages but with the ability to associate data with each case. For example: type Shape = Circle of float | Rectangle of float * float | Triangle of float * float * float. This defines a `Shape` type that can be a `Circle` (with radius), `Rectangle` (with width and height), or `Triangle` (with three sides).

5. How do you perform asynchronous operations in F#?

   • Answer: F# uses asynchronous workflows (`async { ... }`) to perform asynchronous operations. These workflows use the `Async` type, allowing for sequencing and composition of asynchronous operations while maintaining readability. The `Async.RunSynchronously` function is used to start and wait for completion of an asynchronous operation.

Thank you for reading our blog post on 'F# Interview Questions and Answers for 10 years experience'.We hope you found it informative and useful.Stay tuned for more insightful content!