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

Chris Bahr
Chris Bahr
5,614 Points
Posted by Chris Bahr
Chris Bahr
5,614 Points

How can I retrieve the values passed in as a dictionary to construct the failable initializer?

I can't syntactically figure it out, should I be using guard?

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

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

1 Answer

Thomas Dobson
Thomas Dobson
7,511 Points
Thomas Dobson
Thomas Dobson
7,511 Points

You were really close:

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"]
    }
}

I hope this helps