How to filter API Response to include/exclude some data from TableView in Swift

Question

I'm trying to exclude some data I'm receiving from API response,

API Response:

{"status":"ok","answer":[{
                    address = Newyork;
                    comments = test;
                    "contact_name" = "[email protected]";
                    status = "4";
                    },
                    {
                    address = Ohio;
                    comments = test;
                    "contact_name" = "[email protected]";
                    "status" = "3";
                    },
                    {
                    address = cityname;
                    comments = test;
                    "contact_name" = "[email protected]";
                    status = "3";
                    },
                    {
                    address = Washington;
                    comments = test;
                    "contact_name" = "[email protected]";
                    status = "4";
      }
      )
      )

What I'm trying to achieve is, to filter this response, and view only the orders that have status "4" in TableView.

Here is what I tried so far:

func getOrdersHistory() {

    DispatchQueue.main.async {

        let headers = [
            "content-type" : "application/x-www-form-urlencoded",
            "cache-control": "no-cache",
            "postman-token": "dded3e97-77a5-5632-93b7-dec77d26ba99"
        ]

        let user  = CoreDataFetcher().returnUser()
        let email = user.email!

        let postData = NSMutableData(data: "data={\"email\":\"\(email)\",\"type_id\":\"2\"}".data(using: String.Encoding.utf8)!)
        let request = NSMutableURLRequest(url: NSURL(string: "http://www.someApi/Orders")! as URL,
                                          cachePolicy: .useProtocolCachePolicy,
                                          timeoutInterval: 10.0)

        request.httpMethod          = "POST"
        request.allHTTPHeaderFields = headers
        request.httpBody            = postData as Data

        let session  = URLSession.shared
        let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
            if (error != nil) {
                print(error!)
            } else {
                if let dataNew = data, let responseString = String(data: dataNew, encoding: .utf8) {
                    print(responseString)


                    let dict = self.convertToDictionary(text: responseString)
                    print(dict?["answer"] as Any)
                    self.responseArray = (dict?["answer"] as! NSArray) as! [ConfirmedOrders.JSONDictionary]
                    DispatchQueue.main.async {
                        self.tableView.reloadData()
                    }


                }

            }

        })

        dataTask.resume()
    }
}

func convertToDictionary(text: String) -> [String: Any]? {
    if let data = text.data(using: .utf8) {
        do {
            return try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]

        } catch {
            print(error.localizedDescription)
        }
    }
    return nil
}

This way, I'm getting in TableView, regardless of their status, Can anyone help please?

Answer 1

Based on your dataset and using pure Swift arrays and dictionaries, you can simply filter like so:

func getConfirmedOrders(in dict: [String:Any]) -> [[String:Any]] {
    guard
        let answers = dict["answer"] as? [[String:Any]]
        else { print("Answer key not present"); return [] }
    
    //Your basic filter operation
    let filtered = answers.filter { (answer) -> Bool in
        return answer["status"] as? String == "4"
    }
    
    return filtered
}

It's just about proper type casting and then applying the filter operation on it.

Simply using it like so:

self.responseArray = self.getConfirmedOrders(in: dict)
DispatchQueue.main.async {
    self.tableView.reloadData()
}

However, I see that your responseArray is of type [ConfirmedOrders.JSONDictionary].
So either change getConfirmedOrders(from:) to return [ConfirmedOrders.JSONDictionary] or change your responseArray to be of type [[String:Any]].

---

Playground Example

let jsonString = """
{"status":"ok","answer":[{"address":"Newyork","comments":"test","contact_name":"[email protected]","status":"4"},{"address":"Ohio","comments":"test","contact_name":"[email protected]","status":"3"},{"address":"cityname","comments":"test","contact_name":"[email protected]","status":"3"},{"address":"Washington","comments":"test","contact_name":"[email protected]","status":"4"}]}
"""

if let data = jsonString.data(using: .utf8) {
    do {
        //basically what you have in `convertToDictionary(text:)`
        let dict = try JSONSerialization.jsonObject(with: data, options: []) as! [String: Any]

        let filtered = getConfirmedOrders(in: dict)
        print(filtered)
    }
    catch {
        print(error)
    }
}

---

Suggestions:

1. Use Codable models instead of Swift array and dictionary
2. Use Swift Array instead of NSArray, and similarly use Swift Dictionary instead of NSDictionary

Answer 2

You need

do {

    let dec = JSONDecoder()
    dec.keyDecodingStrategy = .convertFromSnakeCase
    let res = try dec.decode(Root.self, from: data)
     // here filter like e.x
     let filtered = res.answer.filter { $0.status == "4" }
}
catch{
    print(error)
}

---

struct Root: Codable {
    let status: String
    let answer: [Answer]
}

struct Answer: Codable {
    let address, comments, contactName, status: String
}

---

If you need to git rid of Root then do

do {

    guard let data = data else { return }
    let dic = try JSONSerialization.jsonObject(with:data, options: []) as! [String:Any]
    let dataAns = try JSONSerialization.data(withJSONObject:dic["answer"]!, options: [])

    let dec = JSONDecoder()
    dec.keyDecodingStrategy = .convertFromSnakeCase
    let res = try dec.decode([Answer].self, from: dataAns)
     // here filter like e.x
     let filtered = res.filter { $0.status == "4" }
}
catch{
    print(error)
}