Overcomplicated enum

You're not the only one to think this: https://teamtreehouse.com/community/why-arent-we-using-the-raw-values-of-the-enum

I think the instructor here is trying to keep things simple while illustrating the usefulness of Enums. In this case, the implementation may have ended up slightly contrived for the tutorials sake. Of course we are all encouraged to investigate alternative approaches.

I too arrived at a similar approach, with the small addition of appending ".png" to the string returned by .rawValue.

My approach looked like this:

enum Icon: String {
    case ClearDay          = "clear-day"
    case ClearNight        = "clear-night"
    case Rain              = "rain"
    case Snow              = "snow"
    case Sleet             = "sleet"
    case Wind              = "wind"
    case Fog               = "fog"
    case Cloudy            = "cloudy"
    case PartlyCloudyDay   = "partly-cloudy-day"
    case PartlyCloudyNight = "partly-cloudy-night"
    case Default           = "default"

    func toImage() -> UIImage? {
        return UIImage(named: "\(self.rawValue).png")
    }
}

Additionally I switched up the icon init to allow the let keyword (the instructor mentions this in the video)

if  let iconString = weatherDictionary["icon"] as? String,
    let weatherIcon: Icon = Icon(rawValue: iconString) {

    icon = weatherIcon.toImage()
 } else {
    icon = Icon(rawValue: "default")?.toImage()
 }

The switch statement assigns the proper image to the UIImageView depending on the data retrieved from the weather API. Without the switch statement, we would not know which icon would be assigned to the corresponding weather icon from the weather API. If it meets the certain case that image is assigned to the UIImageView.

It seems you are mixing values. Usually I start to question myself when I see repetition in an enum. You might consider 2 enums (or more):

enum TimeOfDay {
  case Day
  case Night
}

enum Weather {
  case Rain
  case Snow
  case Sleet
}

As I look at this, I could see having a Precipitation enum, a Sky enum (clear, cloudy, foggy). With associated values, you could wrangle these in to something pretty flexible. In your current enum, you would have to add values for every possible combination. What happens when it's raining and foggy? Or a cloudy night vs day?

This is a good course on enums: https://teamtreehouse.com/library/swift-20-enumerations-and-optionals

Hope this helps a little!