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

Yuanzheng Wen
Yuanzheng Wen
Courses Plus Student 1,756 Points

Code run in playground, but not accepted by system

I have following code, and run into error saying my init method doesn't accept input var.

struct Book {
    let title: String
    let author: String
    let price: String?
    let pubDate: String?
    init? (dict: Dictionary<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"]

1 Answer

Nathan Tallack
Nathan Tallack
22,159 Points

You were close. You should declare your dictionary type with the following syntax in the first line of your init? method.

init? (dict: [String: String]) {

When we are saying a dictionay of key String value String it looks like [String: String]. Take care not to confuse with an array where it would be just [String]. The fact that we have a type then a colon and then a type inside the square brackets make it clear to the compiler that it is a dictionary type not an array type. :)