Is it possible to generate enum from Array<String> in Swift?

Question

Here is my enum:

enum myEnum : Int {
    case apple = 0
    case orange
    case lemon
}

I would like to create it from an array. The array elements could be the name of the enums.

let myEnumDictionary : Array<String> = ["apple","orange","lemon"]

So is it possible to create enums from an array?

Answer 1

No, it's not possible. In the same way you can't create classes from arrays.

Enums must be compiled. You can't create them dynamically.

Answer 2

If your enum rawValue must be an Int, you could either map from an array of integer raw values to a collection of enums, or add a convenience initializer which returns the enum matching a given string literal:

enum MyEnum : Int {
    case apple = 0
    case orange
    case lemon

    init?(fruit: String) {
        switch fruit {
        case "apple":
            self = .apple
        case "orange":
            self = .orange
        case "lemon":
            self = .lemon
        default:
            return nil
        }
    }
}

let myEnumDictionary = [0, 1, 2].map{ MyEnum(rawValue: $0) }.flatMap{ $0 }

let myEnumDictionary2 = ["apple", "orange", "lemon"].map{ MyEnum(fruit: $0) }.flatMap{ $0 }

If the enum rawValue type was a string, you wouldn't need to provide an initializer:

enum MyEnum: String {
    case apple
    case orange
    case lemon
}

let myEnumDictionary = ["apple", "orange", "lemon"].map{ MyEnum(rawValue: $0) }.flatMap{ $0 }

Of course, the easiest way to create an array of enums is just to provide a literal list of enums:

let myEnumDictionary: [MyEnum] = [.apple, .orange, .lemon]