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

Posted by Paul Westbrook
Paul Westbrook
11,340 Points

Not sure what I am doing wrong - nothing shows up in the preview as errors but it says it can't compile my code.

See my attached code. Not sure where I am going wrong but I was a little thrown off by the two optionals in this example rather than the one optional for address that we were shown in the lessons.

optionals.swift 
struct Book {
    let title: String
    let author: String
    let price: String?
    let pubDate: String?

}
func createBook(dict: [String: String]) -> Book? {
  guard let title = dict["title"], author = dict["author"] else {
    return nil
  }

  let price = dict["address"], pubDate = dict["pubDate"]

  return Book(title: title, author: author, price: price, pubDate: pubDate)

}

2 Answers

jcorum
jcorum
71,830 Points

First, you were asked to create a failable initializer, not a function. Second, it has to be inside the struct rather than outside.

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

    init?(dict: [String: String]) {
        guard let title = dict["title"], let author = dict["author"] else {
            return nil
        }

        self.title = title
        self.author = author
        self.price = dict["price"]
        self.pubDate = dict["pubDate"]
    }

}
Paul Westbrook
Paul Westbrook
11,340 Points

Thanks! That worked.

jcorum
jcorum
71,830 Points
jcorum
jcorum
71,830 Points

You are welcome. Happy coding!