Convert Array to JSON

func convertToJSON(arrayObject: [Any]) -> String? {
        do {
            let jsonData: Data = try JSONSerialization.data(withJSONObject: arrayObject, options: [])
            if let jsonString = NSString(data: jsonData, encoding: String.Encoding.utf8.rawValue) {
                return jsonString as String
            }
        }
        catch let error as NSError {
            print(error.localizedDescription)
        }
        return nil
    }


let array = [["one" : 1], ["two" : 2], ["three" : 3], ["four" : 4]]
let jsonString = convertIntoJSONString(arrayObject: array)
print("jsonString - \(jsonString)")

Call this function with parameter argument as array with type ‘Any’. It will return you a json string. Json string is used to submit array in web service call as request input parameter in Swift.