Result of initializer unused - json

Question

I was just wondering why I get this error. I have struct as 'Model' and initialize it from the extract_data function, which is called in viewDidLoad(), but when I set a breakpoint in the struct I can see that everything was initialised properly and whats strange to is if i take my label and set it to my Struct.base String, it doesn't work somehow...I'm a beginner so an explanation would really be appreciated:)
Here is my ViewController:
override func viewDidLoad() {
super.viewDidLoad()
get_data("https://api.fixer.io/latest?base=CHF")
testLabel.text = TestStruct().base
//ANOTHER ERROR HERE (MISSING ARGUMENT FOR PARAMETER "base" IN CALL)
}
#IBOutlet var testLabel: UILabel!
var test:[TestStruct] = [TestStruct]()
func get_data(_ link:String){
let url:URL = URL(string: link)!
let sessioin = URLSession.shared
let request = URLRequest(url: url)
let testtask = sessioin.dataTask(with: request, completionHandler: { (data, response, error) in
self.extract_data(data)
})
testtask.resume()
}
func extract_data(_ data:Data?){
let json:Any?
if(data==nil){
return
}
do {
json = try JSONSerialization.jsonObject(with: data!, options: [])
//The whole JSON
let data_dictonary = json as? [String: Any]
//Just the "base"
let data_base = data_dictonary?["base"] as! String
print(data_base)
//Just the "date"
let data_date = data_dictonary?["date"] as! String
print(data_date)
//All the exchange rates
let data_rates = data_dictonary?["rates"] as! [String: Double]
print(data_rates)
TestStruct.init(base: data_base, date: data_date, rates: data_rates)
//ERROR IS HERE
}catch {
return
}
}
Here is my Model:
struct TestStruct {
var base: String
var date: String
var rates: [String: Double]
init(base: String, date: String, rates: [String:Double]) {
self.base = base
self.date = date
self.rates = rates
}
}

Answer 1

Your syntax for calling the initializer is incorrect. Change:
TestStruct.init(base: data_base, date: data_date, rates: data_rates)
to:
let someVar = TestStruct(base: data_base, date: data_date, rates: data_rates)
And the error with:
testLabel.text = TestStruct().base
is that you are trying to access the base property on a newly created TestStruct instance but you have no init on your TestStruct with no parameters.
You need to create TestStruct by passing all of the required arguments but that seems pointless since all you want is its base and you need the base to create the instance to begin with.