convert json data to array in swift3

Question

I would like to convert my json response to an array but it doesn't work and I got an error that says my items in the array are nil

func getcomments(){
    RestApiManager.sharedInstance.getComments(TUTORIAL_ID: id){
        response in
        let comments = JSON(response)

        for item in comments.array!{
            let comment = Comment(memail:  String(describing: item["email"]), mcomment:  String(describing: item["comment"]), mcomment_date:  String(describing: item["comment_date"]), manswer:  String(describing: item["answer"]), manswer_date:  String(describing: item["answer_date"]))
            self.comments.append(comment)
        }
    }
}

it is my json response:

   [{
        "email": "-",
        "comment": "\u0627\u0632 \u0627\u067e\u0644\u06cc\u06a9\u06cc\u0634\u0646 \u062e\u0648\u0628\u062a\u0648\u0646 \u0645\u0645\u0646\u0648\u0646\u0645",
        "comment_date": "2017-07-15 19:30:00",
        "answer": null,
        "answer_date": null
    },
    {
        "email": "[email protected]",
        "comment": "salam",
        "comment_date": "2017-07-11 19:30:00",
        "answer": "\u062a\u0634\u06a9\u0631",
        "answer_date": "2017-07-12 03:50:57"
    }
]

I got nil error in this line:

unexpectedly found nil while unwrapping an Optional value

for item in comments.array!

Right here comments.array! If you're going to bang something you best be sure that it is not nil. I don't think you can guarantee that here. Obviously not, because it crashed. — Abizern
– Abizern, Commented Aug 14, 2017 at 9:20
What is the type of response? If it is a string you need to use JSON(parseJSON:) — Sweeper
– Sweeper, Commented Aug 14, 2017 at 9:25
@fazed I posted as an answer. Please consider accepting it by clicking on that checkmark! — Sweeper
– Sweeper, Commented Aug 14, 2017 at 10:09

Sweeper · Accepted Answer · 2017-08-14 10:08:04Z

1

According to your comment, response is actually a string. Therefore, you can't just create a JSON using init(_:). You need init(parseJSON:).

init(_:) will just create a JSON with just that string instead of a JSON object, which is obviously not what you want. init(parseJSON:) will actually parse your JSON string and allow you to access the different key value pairs.

func getcomments(){
    RestApiManager.sharedInstance.getComments(TUTORIAL_ID: id){
        response in
        let comments = JSON(parseJSON: response)

answered Aug 14, 2017 at 10:08

Sweeper

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Comments

Ioana Surdu Bob · Accepted Answer · 2017-08-14 09:34:34Z

1

It's easier if you decode it as an array of structures.

First, create the struct:

struct Comment: Codable {
  var email: String
  var comment: String
  var comment_date: String
  var answer: String
  var answer_date: String
}

Then you can just call the JSON like that:

guard let url = Bundle.main.url(forResource: resource, withExtension: "json") else {
    throw Errors.couldNotFindResource
}
data = try! JSONDecoder().decode([Comment].self, from: Data(contentsOf: url))

answered Aug 14, 2017 at 9:34

Ioana Surdu Bob

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