index of CaseIterable enum

CaseIterable+Index.swift

/*
Copyright (c) 2018 Kazume Koze
Released under the MIT license
https://opensource.org/licenses/mit-license.php
*/

//
//  CaseIterable+Index.swift
//
//
//  Created by Kazuma Koze on 2018/10/06.
//  Copyright © 2018年 Climb App. All rights reserved.
//

import Foundation

extension Hashable where Self : CaseIterable {
    var index: Self.AllCases.Index {
        return type(of: self).allCases.firstIndex(of: self)!
    }
}

EnumIndex1.swift

enum Animal: Int {
    case dog
    case cat
    case rabbit
}

let index: Int = Animal.cat.rawValue

EnumIndex2.swift

enum Animal: Int, CaseIterable {
    case dog = 1
    case cat = 3
    case rabbit = 4
}

let index: Int = Animal.allCases.firstIndex(of: .cat)!

EnumIndex3.swift

enum Animal: String, CaseIterable {
    case dog = "イヌ"
    case cat = "ネコ"
    case rabbit = "うさぎ"
}

let index: Int = Animal.allCases.firstIndex(of: .cat)!

EnumIndex4.swift

enum Animal: CaseIterable {
    case dog
    case cat
    case rabbit
}

let index: Int = Animal.allCases.firstIndex(of: .cat)!

EnumIndex5.swift

enum Animal: CaseIterable {
    case dog
    case cat
    case rabbit
}

let index: Int = Animal.cat.index