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

Posted by Carl Smith
Carl Smith
8,185 Points

How do I create the "dict" parameter?

How do I create the "dict" parameter? Note sure how to perform that part of the task?

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

    init?(title: String, author: String, price: String, pubDate: String) {
       self.title = title
        self.author = author
        self.price = price
        self.pubDate = pubDate
    }
}

2 Answers

Fernando Boza
Fernando Boza
25,384 Points

well of course 

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

// to create the instance we need to initialise it like below, 
//and since the dictionary has a key and value, we must return 2 strings like so below
    init?(dict: [String: String]){

      //so we just created the beginning of the init but didn't finish it, below is
     // the rest. You should get familiar with the Guard let and if let statements.
        guard let title = dict["title"], author = dict["author"] else {
            return nil
        }
        self.title = title
        self.author = author
        self.price = dict["price"]
        self.pubDate = dict["pubDate"]

    }
}
Carl Smith
Carl Smith
8,185 Points

Thank you, I was confused. I usually have trouble with these challenges. However, when it's something I want to do, I usually have no problem figuring things out. Thank you for the help, I'm going to revisit those videos and try to reinforce my knowledge on this subject.

Fernando Boza
Fernando Boza
25,384 Points
Fernando Boza
Fernando Boza
25,384 Points

Hi Carl remember 

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

// to create the instance we need to initialise it like below, 
//and since the dictionary has a key and value, we must return 2 strings like so below
    init?(dict: [String: String]){
Carl Smith
Carl Smith
8,185 Points

I'm still confused. Xcode says I can only return "nil". So I do and it's still not working on the challenge? I still need help :/

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

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