Swift4 で enum を配列として扱う簡単な方法

• enum に CaseIterable を継承させる。
  • allClases が使えるようになる。

enum.playground

import Foundation

enum Numbers: String, CaseIterable {
    case one = "1st"
    case two = "2nd"
    case three = "3rd"
    case four = "4th"
    case five = "5th"
    
    static func get(name: String) -> Numbers? {
        for list in Numbers.allCases {
            if list.rawValue == name {
                return list
            }
        }
        return nil
    }
}

Numbers.get(name: Numbers.two.rawValue) // two

Numbers.allCases // [one, two, three, four, five]

for list in Numbers.allCases {
    print(list.rawValue)
	// 1st
	// 2nd
	// 3rd
	// 4th
	// 5th
}