Given the following enum:
enum Audience {
case Public
case Friends
case Private
}
How do I get the string "Public" from the audience constant below?
let audience = Audience.Public
Not sure in which Swift version this feature was added, but right now (Swift 2.1) you only need this code:
enum Audience : String {
case public
case friends
case private
}
let audience = Audience.public.rawValue // "public"
When strings are used for raw values, the implicit value for each case is the text of that case’s name.
[...]
enum CompassPoint : String { case north, south, east, west }In the example above, CompassPoint.south has an implicit raw value of "south", and so on.
You access the raw value of an enumeration case with its rawValue property:
let sunsetDirection = CompassPoint.west.rawValue // sunsetDirection is "west"
The idiomatic interface for 'getting a String' is to use the CustomStringConvertible interface and access the description getter. Define your enum as:
enum Foo : CustomStringConvertible {
case Bing
case Bang
case Boom
var description : String {
switch self {
// Use Internationalization, as appropriate.
case .Bing: return "Bing"
case .Bang: return "Bang"
case .Boom: return "Boom"
}
}
}
In action:
> let foo = Foo.Bing
foo: Foo = Bing
> println ("String for 'foo' is \(foo)"
String for 'foo' is Bing
Updated: For Swift >= 2.0, replaced Printable with CustomStringConvertible
Note: Using CustomStringConvertible allows Foo to adopt a different raw type. For example enum Foo : Int, CustomStringConvertible { ... } is possible. This freedom can be useful.
For now, I'll redefine the enum as:
enum Audience: String {
case Public = "Public"
case Friends = "Friends"
case Private = "Private"
}
so that I can do:
audience.toRaw() // "Public"
But, isn't this new enum definition redundant? Can I keep the initial enum definition and do something like:
audience.toString() // "Public"
I like to use Printable with Raw Values.
enum Audience: String, Printable {
case Public = "Public"
case Friends = "Friends"
case Private = "Private"
var description: String {
return self.rawValue
}
}
Then we can do:
let audience = Audience.Public.description // audience = "Public"
or
println("The value of Public is \(Audience.Public)")
// Prints "The value of Public is Public"
It couldn't get simpler than this in Swift 2 and the latest Xcode 7 (no need to specify enum type, or .rawValue, descriptors etc...)
Updated for Swift 3 and Xcode 8:
enum Audience {
case Public
case Friends
case Private
}
let audience: Audience = .Public // or, let audience = Audience.Public
print(audience) // "Public"
A swift 3 and above example if using Ints in Enum
public enum ECategory : Int{
case Attraction=0, FP, Food, Restroom, Popcorn, Shop, Service, None;
var description: String {
return String(describing: self)
}
}
let category = ECategory.Attraction
let categoryName = category.description //string Attraction
For anyone reading the example in "A Swift Tour" chapter of "The Swift Programming Language" and looking for a way to simplify the simpleDescription() method, converting the enum itself to String by doing String(self) will do it:
enum Rank: Int
{
case Ace = 1 //required otherwise Ace will be 0
case Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten
case Jack, Queen, King
func simpleDescription() -> String {
switch self {
case .Ace, .Jack, .Queen, .King:
return String(self).lowercaseString
default:
return String(self.rawValue)
}
}
}
After try few different ways, i found that if you don't want to use:
let audience = Audience.Public.toRaw()
You can still archive it using a struct
struct Audience {
static let Public = "Public"
static let Friends = "Friends"
static let Private = "Private"
}
then your code:
let audience = Audience.Public
will work as expected. It isn't pretty and there are some downsides because you not using a "enum", you can't use the shortcut only adding .Private neither will work with switch cases.
There are multiple ways to do this. Either you could define a function in the enum which returns the string based on the value of enum type:
enum Audience{
...
func toString()->String{
var a:String
switch self{
case .Public:
a="Public"
case .Friends:
a="Friends"
...
}
return a
}
Or you could can try this:
enum Audience:String{
case Public="Public"
case Friends="Friends"
case Private="Private"
}
And to use it:
var a:Audience=Audience.Public
println(a.toRaw())
Friendly by guides if you need to use static strings as enum values:
class EncyclopediaOfCats {
struct Constants {
static var playHideAndSeek: String { "Play hide-and-seek" }
static var eat: String { "Eats" }
static var sleep: String { "Sleep" }
static var beCute: String { "Be cute" }
}
}
enum CatLife {
case playHideAndSeek
case eat
case sleep
case beCute
typealias RawValue = String
var rawValue: String {
switch self {
case .playHideAndSeek:
return EncyclopediaOfCats.Constants.playHideAndSeek
case .eat:
return EncyclopediaOfCats.Constants.eat
case .sleep:
return EncyclopediaOfCats.Constants.sleep
case .beCute:
return EncyclopediaOfCats.Constants.beCute
}
}
init?(rawValue: CatLife.RawValue) {
switch rawValue {
case EncyclopediaOfCats.Constants.playHideAndSeek:
self = .playHideAndSeek
case EncyclopediaOfCats.Constants.eat:
self = .eat
case EncyclopediaOfCats.Constants.sleep:
self = .sleep
case EncyclopediaOfCats.Constants.beCute:
self = .beCute
default:
self = .playHideAndSeek
}
}
}
I agree with all the above answers but in your enum private and the public cases can't be defined since those are default keywords. I'm including CaseIterable in my answer, it may help you to get all cases if you required to loop over.
enum Audience: String, CaseIterable {
case publicAudience
case friends
case privateAudience
var description: String {
switch self {
case .publicAudience: return "Public"
case .friends: return "Friends"
case .privateAudience: return "Private"
}
}
static var allAudience: [String] {
return Audience { $0.rawValue }
}
}
print("\(audience)")- gbdavidString(describing: yourEnumValue)- Travis Griggs