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Silvio Colman
Asked: 2020-09-12 20:56:44 +0800 CST 2020-09-12 20:56:44 +0800 CST

Error accessing Dictionary value in Swift 3

  • 772

I have the following json

{
   [
          {
            "id": "c200",
            "dia": "Lunes",
            "horario": "07:30/09:20",
            "materia": "Dibujo Tecnico (T)",
            "seccion": "A",
            "profesor" : "Ernesto Arce",
            "aula" : "D1"
          },
          {

            "id": "c383",
            "dia": "Martes",
            "horario": "20:00/21:50",
            "materia": "Sistemas de Telefonia (T)",
            "seccion": "A",
            "profesor" : "-",
            "aula" : "CITEC"

            },
            {

            "id": "c486",
            "dia": "Miercoles",
            "horario": "20:00/21:50",
            "materia": "Materiales 1 (T)",
            "seccion": "A",
            "profesor" : "Gustavo Roman",
            "aula" : "F3"

            }


        ]
}

What I do is convert this Json into a Dictionary Array so that I can access the values ​​of each one. I do that with the help of my following code

import UIKit
import Alamofire



extension MockData {

    static func index(completion: @escaping ([MockData]) -> Void) {

        Alamofire.request("https://www.dropbox.com/s/fem028u5ok95270/Clases.json?dl=1") .responseJSON { (response) in
            print(response)
            var users = [MockData]()
            if let objects = response.result.value {
                let json = objects as! NSDictionary
                let list = json["Horario"] as? [[String: AnyObject]]

            for object in list! {
                users.append(MockData(dictionary: object))
            }
            }
            completion(users)

        }

    }
}

import UIKit

class MockData: NSObject {

var id : String?
var dia : DiasClases?
var materia : String?
var horario : String?
var seccion : String?
var profesor : String?
//var aula : String?
//var obs : String?
var HorarioArray = [MockData]()


init(dictionary: [String: AnyObject]){

    self.id = dictionary["id"] as? String
    self.dia = dictionary["dia"] as? DiasClases
    self.materia = dictionary["materia"] as? String
    self.horario = dictionary["horario"] as? String
    self.seccion = dictionary["seccion"] as? String
    self.profesor = dictionary["profesor"] as? String
    //self.aula = dictionary["aula"] as? String
    //self.obs = dictionary["obs"] as? String

      }


   }


enum DiasClases {
case Lunes
case Martes
case Miercoles
case Jueves
case Viernes
case Sabado

static func AllValues() -> [DiasClases] {
    return [Lunes, Martes, Miercoles, Jueves, Viernes, Sabado]
  }
}

The problem I have is that when I debug my program and verify that the array is loaded with the correct data, the day item does not contain anything, it only says ClassDays? and I do not save the value of the day. I would greatly appreciate your help. Cheers!

json

2 Answers

  1. Best Answer

    In the JSON, day is not of type DiaClases, it is of type String. What you have to do is first get the day and then convert it to the corresponding DiaClases. In the init take the day and then save it as it should be

    let d = dictionary["dia"] as? String
switch d {
   case "Lunes":
       self.dia = .Lunes
   case "Martes":
       self.dia = .Martes
 .....
}
    • 1

  2. Using the following code:

    let self.dia = DiasClases(rawValue: dictionary["dia"])!

    You get the Enumerator that corresponds to the value you pass to it with dictionary["dia"].

    In order to use this method in enumerators with types other than Stringyou must declare them RawValueas follows:

    Example with Int:

    First we define which is the one RawValueof the enumerators in the following way:

    enum DiasClases: Int {
case Lunes = 1
case Martes = 2
case Miercoles = 3
case Jueves = 4
case Viernes = 5
case Sabado = 6
}

    Once you have those RawValuedeclared, we can use the statement to look up the enumerator of the value you pass to it:

    Example searching for Wednesday:

    let self.dia = DiasClases(rawValue: 3)!
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