Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

iOS Swift 2.0 Enumerations and Optionals Introduction to Optionals Initializing Optional Values

Tried the code in a playground of Xcode 7 - it's OK. Don't see any errors in a preview Window here.

struct Book {
    let title: String
    let author: String
    let price: String?
    let pubDate: String?

    init?(arr: [String : String]) {
      if arr["title"] == nil {return nil}
      if arr["author"] == nil {return nil}
      self.title = arr["title"]!
      self.author = arr["author"]!
      self.price = arr["price"]
      self.pubDate = arr["pubDate"]

I'd very appreciate if you could tell me where I'm wrong.

ok. it should be dict instead of arr - I know :)

1 Answer

Jens Hagfeldt
Jens Hagfeldt
16,548 Points


Yes you should use dict instead of arr if you want to pass the code challenge... Naming is crucial.

Also when checking your non-optional keys, instead of using if arr["title"] == nil {return nil} try in using the guard syntax that Pasan showed us in the previous video to check for that first instead. I've included the code for that down here below...

guard let bookTitle = dict["title"], bookAuthor = dict["author"] else {
   return nil

I hope this helped a bit... Happy coding!

/ Jens