Optionals

optionals.swift

struct Person {
    let firstName: String
    let middleName: String?
    let lastName: String
    
    func getFullName() -> String {
        if middleName == nil {
            return firstName + " " + lastName
        } else {
            return firstName + " " + middleName! + " " + lastName
        }
    }
}

let me = Person(firstName: "Pasan", middleName: nil, lastName: "Premaratne")

me.getFullName()

let airportCodes = ["CDG": "Charles de Gaulle"]

if let newYorkAirport = airportCodes["JFK"] {
    print(newYorkAirport)
} else {
    print("Whoops that key does not exist!")
}

let weatherDictionary: [String: [String: String]] = ["currently": ["temperature": "22.3"], "daily": ["temperature": "22.3"], "weekly": ["temperature": "22.3"]]

if let dailyWeather = weatherDictionary["daily"], let highTemperature = dailyWeather["temperature"] {
    print(highTemperature)
}

// Bai Tap

let movieDictionary = ["Spectre": ["cast": ["Daniel Craig", "Christoph Waltz", "Léa Seydoux", "Ralph Fiennes", "Monica Bellucci", "Naomie Harris"]]]

var leadActor: String = ""

// Enter code below
if let spectre = movieDictionary["Spectre"], let cast = spectre["cast"] {
    var leadActor = cast[0]
}

struct Friend {
    let name: String
    let age: String
    let address: String?
}

func createFriend(dict: [String: String]) -> Friend? {
//    if let name = dict["name"], let age = dict["age"] {
//        let address = dict["address"]
//        return Friend(name: name, age: age, address: address)
//    } else {
//        return nil
//    }
    guard let name = dict["name"], let age = dict["age"] else {
        return nil
    }
    
    let address = dict["address"]
    return Friend(name: name, age: age, address: address)
}

// Bai tap

struct Book {
    let title: String
    let author: String
    let price: String?
    let pubDate: String?
    
    init?(dict: [String: String]) {
        
        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"]
    }
}