How do I get the count of a Swift enum?

As of Swift 4.2 (Xcode 10) you can declare conformance to the CaseIterable protocol, this works for all enumerations without associated values:

enum Stuff: CaseIterable {
    case first
    case second
    case third
    case forth
}

The number of cases is now simply obtained with

print(Stuff.allCases.count) // 4

For more information, see

• SE-0194 Derived Collection of Enum Cases

I have a blog post that goes into more detail on this, but as long as your enum's raw type is an integer, you can add a count this way:

enum Reindeer: Int {
    case Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen
    case Rudolph

    static let count: Int = {
        var max: Int = 0
        while let _ = Reindeer(rawValue: max) { max += 1 }
        return max
    }()
}