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

What is the solution of this?

I am not sure about the solution. Please let me know if anyone has done this.

Code Challenge:

In the editor, you have a struct named Book which has few stored properties, two of which are optional.

Your task is to create a failable initializer that accepts a dictionary of type [String : String] as input and initializes all the stored properties. (Hint: A failable init method is one that can return nil and is written as init?).

Use the following keys to retrieve values from the dictionary: "title", "author", "price", "pubDate"

Note: Give your initializer argument the name dict

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

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


2 Answers

Dave Harker
Dave Harker
Pro Student 15,510 Points

Hi ,

You've got it started there, just need to work through all objectives.
So let's guard those required variables and deal with failed initialization to meet the requirement:

Your task is to create a failable initializer that accepts a dictionary of type [String : String] as input

With something like this:

guard let title = dict["title"], let author = dict["author"] else {
    return nil

Now that's done we just need to finish up so we can

initializes all the stored properties.

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

Now you just need to put it all together. Keep going!


Thank you Dave!