How to enumerate an enum with String type?

Question

enum Suit: String {     case spades = "♠"     case hearts = "♥"     case diamonds = "♦"     case clubs = "♣" } 

For example, how can I do something like:

for suit in Suit {     // do something with suit     print(suit.rawValue) } 

Resulting example:

♠ ♥ ♦ ♣ 

Answer 1

This post is relevant here https://www.swift-studies.com/blog/2014/6/10/enumerating-enums-in-swift

Essentially the proposed solution is

enum ProductCategory : String {      case Washers = "washers", Dryers = "dryers", Toasters = "toasters"       static let allValues = [Washers, Dryers, Toasters] }  for category in ProductCategory.allValues{      //Do something } 

Answer 2

Swift 4.2+

Starting with Swift 4.2 (with Xcode 10), just add protocol conformance to CaseIterable to benefit from allCases. To add this protocol conformance, you simply need to write somewhere:

extension Suit: CaseIterable {} 

If the enum is your own, you may specify the conformance directly in the declaration:

enum Suit: String, CaseIterable { case spades = "♠"; case hearts = "♥"; case diamonds = "♦"; case clubs = "♣" } 

Then the following code will print all possible values:

Suit.allCases.forEach {     print($0.rawValue) } 

---

Compatibility with earlier Swift versions (3.x and 4.x)

If you need to support Swift 3.x or 4.0, you may mimic the Swift 4.2 implementation by adding the following code:

#if !swift(>=4.2) public protocol CaseIterable {     associatedtype AllCases: Collection where AllCases.Element == Self     static var allCases: AllCases { get } } extension CaseIterable where Self: Hashable {     static var allCases: [Self] {         return [Self](AnySequence { () -> AnyIterator<Self> in             var raw = 0             var first: Self?             return AnyIterator {                 let current = withUnsafeBytes(of: &raw) { $0.load(as: Self.self) }                 if raw == 0 {                     first = current                 } else if current == first {                     return nil                 }                 raw += 1                 return current             }         })     } } #endif