Swift decodable with unknown coding key and value [duplicate]

Answer 1

You can try

let res = try? JSONDecoder().decode([String:Double].self,from:data)
print(res["USD"])

which will enable you to decode any key

Answer 2

When I work with JSONs that are not fully known (as in I know all the possible keys and need all of them) I used SwiftyJSON library: https://github.com/SwiftyJSON/SwiftyJSON

It's much easier to work with than the built in JSON decoder

in your case it would be:

var jsonString = "{\"USD\":6385.74,\"JPY\":715249.73,\"EUR\":5582.36}"
let json = JSON(parseJSON: jsonString)

then you can do a bunch of stuff like iterating over keys

for (key, value) in json {
    if let currency = key.string {
        print (currency,value)
    }
}

Check out the documentation in https://github.com/SwiftyJSON/SwiftyJSON