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

vivek d
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.a{fill-rule:evenodd;}techdegree
vivek d
iOS Development Techdegree Student 1,596 Points
Posted by vivek d
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vivek d
iOS Development Techdegree Student 1,596 Points

can someone explain the question, please?

whats missing?

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

    init?(dict : [String : String]){
      return nil
    }


}

1 Answer

Matthew Long
Matthew Long
28,407 Points
Matthew Long
Matthew Long
28,407 Points

Took me a bit to get this correct. I swear anything to do with optionals are the most difficult thing in swift "basics"..

You'll have to fist use a guard or if let statement to check for/unwrap price and pubDate or return nil. After you've done that you can initialize them as seen below:

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"]
    }
}