Convert JSON nested objects

Question

I am getting the following JSON from Foursquare API and I have been struggling with extracting the data:

{
  "meta":{
    "code":200,
    "requestId":"58122e59498e5506a1b23580"
  },
  "response":{
    "venues":[
      {
        "id":"4d56c381a747b60cd4a12c2b",
        "name":"Sports Circle",
        "contact":{},
        "location":{
          "lat":31.9,
          "lng":35.9,
          "labeledLatLngs":[
            {
              "label":"display",
              "lat":31.9,
              "lng":35.90
            }
          ],
      ],
      "confident":true
    }
  }
}

I want to get the name in venues in addition to the lat and lng values. I have tried this so far but it gets out of the second if statement at JVenues because it is nil:

func parseData (JSONData: Data){
    do {
        var readableJson = try JSONSerialization.jsonObject(with: JSONData, options: .mutableContainers) as! [String:AnyObject]

        if let JResponse = readableJson ["response"] as? [String:AnyObject] {
            if let JVenues = JResponse["venues"] as? [String:AnyObject]{
                if let JName = JVenues["name"] as? String{
                    NSLog(JName)
                }
            }
        }
    } catch {
        print(error)
    }
}

Frankie · Accepted Answer · 2016-10-27 22:50:07Z

2

This is what the other answers are getting at. Will probably make more sense if you can see it all laid out...

if let JResponse = readableJson ["response"] as? [String : AnyObject] {
    if let JVenues = JResponse["venues"] as? [[String : AnyObject]] {
        if let JName = JVenues.first?["name"] as? String {
            NSLog(JName)
        }
    }
}

Note this only gets the FIRST name in the array of venues.

EDIT:

I prefer something like this. Define a struct and convert your dictionaries to the struct:

struct Venue {
    var name: String?
    var venueId: String?

    init(_ venueDictionary: [String : AnyObject]) {
        self.name = venueDictionary["name"] as? String
        self.venueId = venueDictionary["id"] as? String
    }
}

In your class create a property such as:

var venues = [Venue]()

From your JSON map the dictionaries to the venue array. I renamed variables that start with a capital for convention.

if let response = readableJson ["response"] as? [String : AnyObject] {
     if let responseVenues = response["venues"] as? [[String : AnyObject]] {
         self.venues = responseVenues.map({ Venue($0)) })
     }
 }

Use anywhere in your class like:

let venue = self.venues.first
print(venue?.name)

Or:

if let venue = self.venues.find({ $0.name == "Sports Circle" }) {
    print("found venue with id \(venue.venueId)")
}

edited Oct 27, 2016 at 22:50

answered Oct 27, 2016 at 18:57

Frankie

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3 Comments

Lara Over a year ago

thank you for your clarification that worked! I am sorry I am new to swift if I want to access the values in name in a variable it is not clear to me how can I do that? is there a link or a tutorial on how to deal with this?

Frankie Over a year ago

Added additional help. If my answer was helpful to you you can up vote it. Thanks!

Frankie Over a year ago

If you need something more permanent, like info you can access throughout the app and on multiple runs, you'll want to learn Core Data.

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