Enumerate

enum ShirtSize: String {
  case small = "S"
  case medium = "M"
  case large = "L"
  case extraLarge = "XL"
  var description: String {
    return "The size of this shirt is \(self.rawValue)"
  }
}

enum Hello: String {
  case english = "Hello"
  case japanese = "Hello!"
  case emoji = "👋"
}
let hello1 = Hello(rawValue: "Hello!")
let hello2 = Hello(rawValue: "Привет")
print(hello1) // Optional(Hello.japanese)
print(hello2) // nil

enum Traffic {
  case light
  case heavy
  mutating func reportAccident() {
    self = .heavy
  }
}
var currentTraffic: Traffic = .light
currentTraffic. reportAccident()
// currentTraffic is now .heavy

Just like classes and structs, enumerations can have instance methods. If an instance method mutates the value of the enum, it needs to be marked mutating

enum Dessert {
  case cake(flavor: String)
  case vanillaIceCream(scoops: Int)
  case brownie
}
let order: Dessert = .cake(flavor: "Red Velvet")

enum Beatle: String {
  case john paul george ringo
}
print("The Beatles are \(Beatle.john.rawValue).")
// print: The Beatles are john.

enum Season: CaseIterable {
  case winter
  case spring
  case summer
  case falls
}
for season in Season.allCases {
  print(season)
}

Add conformance to the CaseIterable protocol to access the allCases property, which returns an array of all cases of the enumeration

enum Day {
  case monday
  case tuesday
  case wednesday
  case thursday
  case friday
  case saturday
  case sunday
}
let casualWorkday: Day = .friday