How do I get a dictionary from an array in Swift 4.2

Question

I've seen a number of similar questions, but none seem to match my use case.

I have a json file structured as follows:

{
    "Trains": [{
        "Car": "8",
        "Destination": "Glenmont",
        "DestinationCode": "B11",
        "DestinationName": "Glenmont",
        "Group": "1",
        "Line": "RD",
        "LocationCode": "A06",
        "LocationName": "Van Ness-UDC",
        "Min": "3"
    }, {
        "Car": "6",
        "Destination": "Shady Gr",
        "DestinationCode": "A15",
        "DestinationName": "Shady Grove",
        "Group": "2",
        "Line": "RD",
        "LocationCode": "A06",
        "LocationName": "Van Ness-UDC",
        "Min": "3"
    
    }]
}

I'm trying to get the dictionaries for each train. I've tried this (amongst other efforts), but I cant get my head around it. Here is my code:

jsonArray = [try! JSONSerialization.jsonObject(with: data!, options: .mutableContainers)] as! [String]
            
            for train in jsonArray {
                print(train["name"])
            }

This doesn't compile.

My jsonArray is set up as:

 var jsonArray = [Any]()

Please read the JSON. It's quite easy. {} is dictionary, [] is array. Therefore the root object is a dictionary ([String:Any]) and the value for key Trains is an array ([[String:Any]]), not [Any]. There is no [String] type at all in the JSON. — vadian
– vadian, Commented Oct 30, 2018 at 16:58

chandra1234 · Accepted Answer · 2018-11-01 07:18:59Z

1

I hope this answer will match your case, check below, Don't get confused I used your JSON response in a file.

if let path = Bundle.main.path(forResource: "file", ofType: "json") {
        do {
            let data1 = try Data(contentsOf: URL(fileURLWithPath: path), options: [])

            let jsonDic = try JSONSerialization.jsonObject(with: data1, options: .mutableContainers) as? [String:Any]
            guard let dic = jsonDic else { return}
            if let dict = dic["Trains"] as? [[String:Any]]{
                print(dict)
            }
        } catch {
            print(error as NSError)
        }

}

If you want to use a decoder then use this.

struct Result: Decodable {
     let Trains:[transaction]
}
struct transaction: Decodable {
    let Car:String
    let Destination:String
    let DestinationCode:String
}
var result = [Result]()

 if let path = Bundle.main.path(forResource: "file", ofType: "json") {
         do {
            let data1 = try Data(contentsOf: URL(fileURLWithPath: path), options: [])
            let decoder = JSONDecoder()
            result = [try decoder.decode(Result.self, from: data1)]
             print(result)
         } catch {
            print(error)
        }
    }

Feel free to say any mistake is there in my coding.

answered Nov 1, 2018 at 7:18

chandra1234

3676 silver badges15 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

ICL1901 Over a year ago

Thanks for your answer. I did solve the problem along the lines of your answer, so I’ll mark the question as complete.

Collectives™ on Stack Overflow

How do I get a dictionary from an array in Swift 4.2

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related