Swift enum getting value of Int Enum using String value - swift

Question

I have an enum thats raw value is Int. I know How to get the raw value. But I am accessing the data through webservice and there data for Enum is coming in String value.
Let me show you my Enum, then we will discuss the data that need to be convert into Enum and then getting the raw value.
My Enum:
enum ReportStatus : Int {
case None = 0
case Received = 2
case Forward = 9
case Reporting = 14
case Completed = 50
}
and the data I am getting from webservice is sending me value in
string like so
var valueToCompareWithEnum = "Forward"
what I want:
I want to match that string value and to get the resultant int value.
For example as I am receiving "Forward" So I must convert it in enum
and getting the 9 Int value.
I know I can make switch case for it but I wanted to know if it can be handled with more clean way.....
Thanks in advance please help.

Answer 1

You can let your enum implement CaseIterable and then compare your string to the string representation of each enum case using Array.first(where:)
enum ReportStatus : Int, CaseIterable {
case None = 0
case Received = 2
case Forward = 9
case Reporting = 14
case Completed = 50
static func translate(_ string: String) -> Int? {
return ReportStatus.allCases.first(where: {string == "\($0)"})?.rawValue
}
}
As a variant here is a global generic function that does the same but it returns the enum case rather than the raw value.
func translate<T: CaseIterable>(_ string: String, forEnum: T.Type) -> T? {
return forEnum.allCases.first(where: {string == "\($0)"})
}
Usage
if let item = translate(valueToCompareWithEnum, forEnum: ReportStatus.self) {
print(item.rawValue)
}

Answer 2

You can code like this;
enum ReportStatus : Int {
case None = 0
case Received = 2
case Forward = 9
case Reporting = 14
case Completed = 50
static func getRawValue(from value : String) -> Int {
switch value {
case "Forward":
return self.Forward.rawValue
case "Received":
return self.Received.rawValue
case "Reporting":
return self.Reporting.rawValue
case "Completed":
return self.Completed.rawValue
default:
return self.None.rawValue
}
}
}
var valueToCompareWithEnum = "Forward"
let myVal = ReportStatus.getRawValue(from: valueToCompareWithEnum)
print(myVal) // 9

Answer 3

Since you're receiving these strings from a server, I assume you mean you're receiving them encoded in JSON. If so, then you likely want them to be Decodable. In that case, you can implement a custom decoder.
Before I show that, I'm going to rename your enum cases to match Swift style, which is a lowercase letter. I'm doing this to make the problem slightly harder and show more techniques you can use.
enum ReportStatus : Int {
case none = 0
case received = 2
case forward = 9
case reporting = 14
case completed = 50
}
Here's the most straightforward approach:
extension ReportStatus: Decodable {
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
let stringValue = try container.decode(String.self)
switch stringValue {
case "None": self = .none
case "Received": self = .received
case "Forward": self = .forward
case "Reporting": self = .reporting
case "Completed": self = .completed
default:
throw DecodingError
.valueNotFound(Self.self,
.init(codingPath: decoder.codingPath,
debugDescription: "Unknown value for report status: \(stringValue)"))
}
}
}
This is a very good technique, but since our case names do match the server's keys closely (just not perfectly), we could fix that up by lowercasing the key:
enum ReportStatus : Int, CaseIterable { // Note CaseIterable
case none = 0
case received = 2
case forward = 9
case reporting = 14
case completed = 50
}
extension ReportStatus: Decodable {
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
let stringValue = try container.decode(String.self)
guard let value = Self.allCases.first(where: { String(describing: $0) == stringValue.lowercased() })
else { throw DecodingError
.valueNotFound(Self.self,
.init(codingPath: decoder.codingPath,
debugDescription: "Unknown value for report status: \(stringValue)"))
}
self = value
}
}

Answer 4

I recommend you switch Int enum to String to make it easer to parse and add one more field to get int value for each case:
enum ReportStatus: String {
case none = "None"
case received = "Received"
case forward = "Forward"
case reporting = "Reporting"
case completed = "Completed"
var intValue: Int {
switch self {
case .none : return 0
case .received : return 2
case .forward : return 9
case .reporting : return 14
case .completed : return 50
}
}
}
let valueToCompareWithEnum = "Forward"
if let myVal = ReportStatus(rawValue: valueToCompareWithEnum) {
print(myVal.intValue) // 9
}
Because that data from web in String format it's kindly recommended parse it to String enum case and then use you'r own Int value where you need.