CODEWITHSUNDEEP
iosarraysjsonswift
MNM
MNM

Reputation: 2743

Loop though a json file and fill in an array Swift

I am trying to loop through a json and place each item into its own array. I don't know how to loop though the json though.I have successfully went though and placed the json once and filled the array, but now I need the whole json into the respected arrays. Any help will be appreciated

Here is what I got:

func parseCoupons(response : String)
{
    print("Starting to parse the file")
    let data = response.dataUsingEncoding(NSUTF8StringEncoding)
    var myJson : NSArray
    myJson = []

    do {
        myJson = try NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments) as! NSArray
    }
    catch {
        print("Error")
    }

    for item in myJson.count {
        titleArray.append((myJson[item]as! NSDictionary)["name"] as! String)
        descriptionArray.append((myJson[item]as! NSDictionary)["description"] as! String)
        amountArray.append((myJson[item]as! NSDictionary)["amount"] as! Int)
        typeArray.append((myJson[item]as! NSDictionary)["type"] as! String)
        startDateArray.append((myJson[item]as! NSDictionary)["start_date"] as! String)
        endDateArray.append((myJson[item]as! NSDictionary)["end_date"] as! String)
        barcodeArray.append((myJson[item]as! NSDictionary)["barcode"] as! String)
    }

And the Json I want to parse will look like this

[
 {
  "name": "Coupon Title",
  "description": "The Coupon Description",
  "type": "PERCENT_OFF",
  "amount": 15,
  "barcode": "4948473",
  "start_date": "2016-12-01",
  "end_date": "2016-12-25",

 },

ECT ECT ECT

]

Upvotes: 0

Views: 1753

Answers (3)

vadian
vadian

Reputation: 285082

Swift is an object oriented language, so create a custom object rather than using a bunch of unrelated arrays.

struct Coupon {

  var name : String
  var description : String
  var amount : Int
  var type : String
  var startDate : String
  var endDate : String
  var barcode : String

}

In parseCoupons use Swift native collection types, the method returns the parsed Coupon items:

func parseCoupons(response : String) -> [Coupon]
{
  print("Starting to parse the file")
  let data = Data(response.utf8)
  var coupons = [Coupon]()

  do {
    let myJson = try JSONSerialization.jsonObject(with: data) as! [[String:Any]]

    for item in myJson {
      let name = item["name"] as! String
      let description = item["description"] as! String
      let amount = item["amount"] as! Int
      let type = item["type"] as! String
      let startDate = item["start_date"] as! String
      let endDate = item ["end_date"] as! String
      let barcode = item["barcode"] as! String
      let coupon = Coupon(name: name,
                          description: description,
                          amount: amount,
                          type: type,
                          startDate: startDate,
                          endDate: endDate,
                          barcode: barcode)
      coupons.append(coupon)
    }
  } catch {
    print("Error", error)
  }
  return coupons
}

Side note: Your do - catch block is meaningless, the good code must be within the do scope and executing the expression myJson[item]as! NSDictionary) again and again in the repeat loop is very inefficient.

Edit

In Swift 4 it became much more convenient.

Adopt Decodable

struct Coupon : Decodable { ...

and enjoy the magic of the protocol

func parseCoupons(response : String) throws -> [Coupon]
{
  print("Starting to parse the file")
  let data = Data(response.utf8)

  let decoder = JSONDecoder()
  decoder.keyDecodingStrategy = .convertFromSnakeCase
  return try decoder.decode([Coupon].self, from: data)
}

Upvotes: 3

MNM
MNM

Reputation: 2743

I got it working by adjusting and playing with the code it works. The for loop structure is very important other wise it won't work just right.

    for i in 0..<myJson.count
    {
        titleArray.append((myJson[i]as! NSDictionary)["name"] as! String)
        descriptionArray.append((myJson[i]as! NSDictionary)["description"] as! String)
        amountArray.append((myJson[i]as! NSDictionary)["amount"] as! Int)
        typeArray.append((myJson[i]as! NSDictionary)["type"] as! String)
        startDateArray.append((myJson[i]as! NSDictionary)["start_date"] as! String)
        endDateArray.append((myJson[i]as! NSDictionary)["end_date"] as! String)
        barcodeArray.append((myJson[i]as! NSDictionary)["barcode"] as! String)
    }

Its very similar to your @Nirav so thanks for leading me to this

Upvotes: 0

Nirav D
Nirav D

Reputation: 72420

Instead of creating multiple array create on which contain Dictionary like this.

var arr : [NSDictionary] = [NSDictionary]()

Now add all your object in this array like this 

for item in myJson.count {
    arr.append(myJson[item] as! NSDictionary)
}

Now you can access each element using dictionary of this array like this 

print((arr[0] as! NSDictionary)["name"] as! String)

Hope this will help you.

Upvotes: 1

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