How to get enum from raw value in Swift?

Question

I'm trying to get enum type from raw value:

enum TestEnum: String {
    case Name
    case Gender
    case Birth

    var rawValue: String {
        switch self {
        case .Name: return "Name"
        case .Gender: return "Gender"
        case .Birth: return "Birth Day"
        }
    }
}

let name = TestEnum(rawValue: "Name")       //Name
let gender = TestEnum(rawValue: "Gender")   //Gender

But it seems that rawValue doesn't work for string with spaces:

let birth = TestEnum(rawValue: "Birth Day") //nil

Any suggestions how to get it?

Answer 1

Too complicated, just assign the raw values directly to the cases

enum TestEnum: String {
  case Name = "Name"
  case Gender = "Gender"
  case Birth = "Birth Day"
}

let name = TestEnum(rawValue: "Name")!       //Name
let gender = TestEnum(rawValue: "Gender")!   //Gender
let birth = TestEnum(rawValue: "Birth Day")! //Birth

If the case name matches the raw value you can even omit it

enum TestEnum: String {
  case Name, Gender, Birth = "Birth Day"
}

In Swift 3+ all enum cases are lowercased

Answer 2

Full working example:

enum TestEnum: String {
    case name = "A Name"
    case otherName
    case test = "Test"
}

let first: TestEnum? = TestEnum(rawValue: "A Name")
let second: TestEnum? = TestEnum(rawValue: "OtherName")
let third: TestEnum? = TestEnum(rawValue: "Test")

print("\(first), \(second), \(third)")

All of those will work, but when initializing using a raw value it will be an optional. If this is a problem you could create an initializer or constructor for the enum to try and handle this, adding a none case and returning it if the enum couldn't be created. Something like this:

static func create(rawValue:String) -> TestEnum {
        if let testVal = TestEnum(rawValue: rawValue) {
            return testVal
        }
        else{
            return .none
        }
    }

Answer 3

With Swift 4.2 and CaseIterable protocol it is not that hard at all!

Here is an example of how to implement it.

import UIKit

private enum DataType: String, CaseIterable {
    case someDataOne = "an_awesome_string_one"
    case someDataTwo = "an_awesome_string_two"
    case someDataThree = "an_awesome_string_three"
    case someDataFour = "an_awesome_string_four"

    func localizedString() -> String {
        // Internal operation
        // I have a String extension which returns its localized version
        return self.rawValue.localized
    }

    static func fromLocalizedString(localizedString: String) -> DataType? {
        for type in DataType.allCases {
            if type.localizedString() == localizedString {
                return type
            }
        }
        return nil
    }

}

// USAGE EXAMPLE
override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    if let dataType = DataType.fromLocalizedString(localizedString: self.title) {
        loadUserData(type: dataType)
    }
}

You can easily modify it to return the DataType based on the rawValue. I hope it helps!

Answer 4

You can define enum like this -

enum TestEnum: String {
    case Name, Gender, Birth
}

OR

enum TestEnum: String {
    case Name
    case Gender
    case Birth
}

you can provide an init method which defaults to one of the member values.

enum TestEnum: String {
    case Name, Gender, Birth

    init() {
        self = .Gender
    }
}

In the example above, TestEnum.Name has an implicit raw value of "Name", and so on.

You access the raw value of an enumeration case with its rawValue property:

let testEnum = TestEnum.Name.rawValue
// testEnum is "Name"
let testEnum1 = TestEnum() 
// testEnum1 is "Gender"

Answer 5

Display the rawvalue using Enum

import UIKit

enum car: String {
    case bmw =  "BMW"
    case jaquar = "JAQUAR"
    case rd = "RD"
    case benz = "BENZ"

}


class ViewController: UIViewController {

    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        label.text = car.bmw.rawValue

    }


}

Answer 6

Here is example of more useable code in swift 4.1

import UIKit

enum FormData {
  case userName
  case password

  static let array = [userName, password]

  var placeHolder: String {
    switch self {
    case .userName:
      return AppString.name.localized // will return "Name" string
    case .password:
      return AppString.password.localized // will return "Password" string
    }
  }
}

enum AppString: String {
  case name = "Name"
  case password = "Password"

  var localized: String {
    return NSLocalizedString(self.rawValue, comment: "")
  }
}

Answer 7

I think this is a quick and clean solution for swift 4.2 (you can c&p to playground)

import UIKit

public enum SomeEnum: String, CaseIterable {
    case sun,moon,venus,pluto
}

let str = "venus"
let newEnum = SomeEnum.allCases.filter{$0.rawValue == str}.first
// newEnum is optional
if let result = newEnum {
    print(result.rawValue)
}