为未知枚举返回相同的原始值

Question

我想为未知枚举返回相同的值，

我在我的代码中定义了以下枚举，

public enum Airport: String {
    case munich = "MUN_T01"
    case sanFrancisco = "SANF_T02"
    case singapore = "SP_T03"

   public var name: String {
        switch self {
        case .munich:
            return "Munich"
        case .sanFrancisco:
            return "San Francisco"
        case .singapore:
            return "Singapore"
   }
}

每当我调用上述枚举时，它都可以正常工作

var airportName = Airport(rawValue: "MUN_T01")
print("Airport Name: ", airportName)   // munich
print("Airport Code: ", airportName.rawValue)   // MUN_T01

现在我想为其他/未知场景覆盖相同的内容，例如，

var unknownAirportName = Airport(rawValue: "Test_T01") ,

应打印unknown或other当我打印unknownAirportName变量，

如果我打印unknownAirportName.rawValue ，它应该打印Test_T01

我能够得到直到其他/未知情况，但我无法打印通过的相同值（Test_T01）。 有什么帮助吗？

Answer 1

考虑用原始值替换 enum 以使用关联的值进行枚举，然后您可以确定已知和未知的情况，例如：

public enum Airport {
    case airport(name: String, code: String)
    case unknown(code: String)
    
    static let airports = [
        Self.airport(name: "Munich", code: "MUN_T01"),
        Self.airport(name: "San Francisco", code: "SANF_T02"),
        Self.airport(name: "Singapore", code: "SP_T03")
    ]
    
    var name: String {
        if case let .airport(name, _) = self {
            return name
        }
        return "Unknown"
    }
    
    var code: String {
        switch self {
            case let .airport(_, code):
                return code
            case let .unknown(code):
                return code
        }
    }
    
    static func airport(code: String) -> Airport {
        if let item = Self.airports.first(where: { $0.code == code }) {
            return item
        }
        return unknown(code: code)
    }
}

let airport = Airport.airport(code: "MUN_T01")
print("Airport:", airport.name, airport.code) // Airport: Munich MUN_T01

let airport2 = Airport.airport(code: "NONE")
print("Airport:", airport2.name, airport2.code) // Airport: Unknown NONE