how to get value from json array in swift4 - ios

Question

I can't getting json value into variable.I'm printing value but the problem is I can't getting json value without array
here is my json
{
"Categories": [
"city",
"delhi"
]
}
I want to categories value with array im printing value with array
here is my code
do{
let json = try JSONSerialization.jsonObject(with: data!, options: []) as! [String: AnyObject]
print(json as AnyObject)
if let Categories = json["Categories"] {
print(Categories)
}

Answer 1

You need
do {
let json = try JSONSerialization.jsonObject(with: data!, options: []) as! [String:[String]]
let arr1 = json["Categories"]!
let str1 = arr1.joined(separator: ":")
print(str1)
// or
let decoded = try JSONDecoder().decode(Root.self, from: data)
let str = decoded.categories.joined(separator: ":")
print(str)
} catch {
print(error)
}
or use
struct Root: Codable {
let categories: [String]
enum CodingKeys: String, CodingKey {
case categories = "Categories"
}
}

Answer 2

Make your life easier with Codable. First create custom model for your response
struct Response: Decodable {
let categories: [String]
enum CodingKeys: String, CodingKey {
case categories = "Categories"
}
}
Then decode your data which your receive using JSONDecoder
if let data = data {
do {
let decoded = try JSONDecoder().decode(Response.self, from: data)
let string = decoded.categories.joined(separator: ", ") // if u need to join
// your array to
// single `String`
print(string)
} catch { print(error) }
}

Answer 3

Use built in swift support for decoding json by conforming to Decodable and also conform to CustomStringConvertible to get a string representation of the values
struct Item: Decodable, CustomStringConvertible {
let categories: [String]
enum CodingKeys: String, CodingKey {
case categories = "Categories"
}
public var description: String {
return categories.joined(separator: " ")
}
}
let decoder = JSONDecoder()
do {
let result = try decoder.decode(Item.self, from: data)
let descr = result.description
print(descr)
} catch {
print(error)
}

Answer 4

//Model Class should be like this
struct JsonResposne : Codable {
let categories : [String]?
enum CodingKeys: String, CodingKey {
case categories = "Categories"
}
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
categories = try values.decodeIfPresent([String].self, forKey: .categories)
}
}
func getCategoriesResponse() {
Alamofire.request(requestUrl, method: .post, parameters: params, encoding: URLEncoding.default).responseJSON { (response) in
switch response.result {
case .success:
if response.data != nil {
do {
let decoder = JSONDecoder()
let apiResponse:JsonResponse = try decoder.decode(JsonResponse.self, from: responseData)
print(apiResponse.categories.count)
}catch {
print(error.localizedDescription)
}
}
}
break
case .failure:
print("There was something with your call")
break
}
}
}