1. This is the response String
{"error_msg": null,"applicationStateJson": {"notifications_size": "0","dfilterlogin": 1,"loginstype": null,"email_status": "0","address_status": "0","defaultfiltername": "hyderabad","login_status": "1","defaultfilterid": 145,"profile_id": null,"freelancer": "Y","otp_status": "1","notifications": []},"status": null}
2. Below one is the perfect JSONObject, I get it to using JSONLint
{
"error_msg": null,
"applicationStateJson": {
"notifications_size": "0",
"dfilterlogin": 1,
"loginstype": null,
"email_status": "0",
"address_status": "0",
"defaultfiltername": "hyderabad",
"login_status": "1",
"defaultfilterid": 145,
"profile_id": null,
"freelancer": "Y",
"otp_status": "1",
"notifications": []
},
"status": null
}
3. When I try the below code in Swift 3
let json1 = try? JSONSerialization.jsonObject(with: data, options: [])
if let object = json1 as? [String: Any]{
if let applicationState = object["applicationStateJson"] as? [String: Any]{
print("applicationState \(applicationState)")
}
}
4. I got JSONObject but it's not a proper JSONObject
(because the commas are changed into semicolon, null values are changed into "< null >" and then empty array [] changed into ())
Optional({
applicationStateJson = {
"address_status" = 0;
defaultfilterid = 145;
defaultfiltername = hyderabad;
dfilterlogin = 1;
"email_status" = 0;
freelancer = Y;
"login_status" = 1;
loginstype = "<null>";
notifications = (
);
"notifications_size" = 0;
"otp_status" = 1;
"profile_id" = "<null>";
};
"error_msg" = "<null>";
status = "<null>";
})
I want the JSONObject like the step 2, any help?
To read and use a JSON response in Swift does not require you to convert the JSON object back to JSON just to get a particular part. Once you have the data loaded into a Swift type you can work directly with it to get the parts you need.
So the long way which explains my point better...
let jsonData = jsonString.data(using: .utf8)!
let json1 = try? JSONSerialization.jsonObject(with: jsonData, options: [])
if let object = json1 as? [String: Any]{
if let applicationState = object["applicationStateJson"] as? [String: Any]{
print("applicationState \(applicationState)")
if let addressStatus = applicationState["address_status"] as? String {
print(addressStatus)
}
}
}
The Swift 4 way of doing this with the Codable Protocol
let jsonString = "{\"error_msg\": null,\"applicationStateJson\": {\"notifications_size\": \"0\",\"dfilterlogin\": 1,\"loginstype\": null,\"email_status\": \"0\",\"address_status\": \"0\",\"defaultfiltername\": \"hyderabad\",\"login_status\": \"1\",\"defaultfilterid\": 145,\"profile_id\": null,\"freelancer\": \"Y\",\"otp_status\": \"1\",\"notifications\": []},\"status\": null}"
struct ApplicationState: Codable {
let notificationsSize: String
let dFilterLogin: Int
let loginsType: String?
let emailStatus: String
let addressStatus: String
enum CodingKeys : String, CodingKey {
case notificationsSize = "notifications_size"
case dFilterLogin = "dfilterlogin"
case addressStatus = "address_status"
case loginsType = "loginstype"
case emailStatus = "email_status"
}
}
struct ApplicationStateResponse: Codable {
let errorMsg: String?
let applicationState: ApplicationState
enum CodingKeys : String, CodingKey {
case errorMsg = "error_msg"
case applicationState = "applicationStateJson"
}
}
let jsonData = jsonString.data(using: .utf8)!
let decoder = JSONDecoder()
let response = try! decoder.decode(ApplicationStateResponse.self, from: jsonData)
let appState = response.applicationState
print(appState.addressStatus)
Both of these print 0 for the address status as expected. one is much easier to work with than the other though.
This article which explains the codable protocol a bit more would be a good read.
Convert Swift Dictionary object to JSON string,
if let theJSONData = try? JSONSerialization.data(withJSONObject: applicationState, options: .prettyPrinted),
let theJSONText = String(data: theJSONData, encoding: String.Encoding.ascii) {
print("JSON string = \n\(theJSONText)")
}
Related
I want to parse a Json file with this structure:
{"x":"exchange","b":"usd","ds":["exchange","avgp","mcap","ppc7D","ppc12h","ppc4h","ppc24h"],"data":[["Dow Jones","16360.447","273.89B","6.62","2.14","-0.59","-1.99"],["Dax","877.422","6.80B","38.15","-7.4","-4.44","-4.12"],["nikkei","30.077","2.96B","24.22","-2.3","-4.02","-4.95"],["ATX","281.509","15.29B","214.97","-5.48","-4.58","-10.77"]]}
I do not know how to parse a Json file where there is no definition like:
exchange = "Dow Jones", avgp = 16360.477" etc.
And i could not found anything online.
My code looks like this:
let json = """
{"x":"exchange","b":"usd","ds":["exchange","avgp","mcap","ppc7D","ppc12h","ppc4h","ppc24h"],"data":[["Dow Jones","16360.447","273.89B","6.62","2.14","-0.59","-1.99"],["Dax","877.422","6.80B","38.15","-7.4","-4.44","-4.12"],["nikkei","30.077","2.96B","24.22","-2.3","-4.02","-4.95"],["ATX","281.509","15.29B","214.97","-5.48","-4.58","-10.77"]]}
""".data(using: .utf8)!
struct JsonWebsocket: Decodable {
let exchange: String
let avgp: String
let mcap: String
let ppc7D: String
let ppc12h: String
let ppc4h: String
let ppc24h: String
init(exchange: String, avgp: String, mcap: String, ppc7D: String, ppc12h: String, ppc4h: String, ppc24h: String) {
self.exchange = exchange
self.avgp = avgp
self.mcap = mcap
self.ppc7D = ppc7D
self.ppc12h = ppc24h
self.ppc4h = ppc4h
self.ppc24h = ppc24h
}
}
func fetchJson() -> [String:JsonWebsocket] {
let jsonCoinsDecode = json
let coinDecode = JSONDecoder()
let output = try! coinDecode.decode([String:JsonWebsocket].self, from: jsonCoinsDecode)
return output
}
let array = fetchDataTradingPairs()
But of course it returns an error as the structure does not match the json file.
Does anyone know how to parse this json?
Thanks!
create a struct like that.
struct JsonWebsocket: Decodable {
let x: String
let b: String
let ds: [String]
let data: [[String]]
}
and decode
do {
let coinDecode = JSONDecoder()
let output = try coinDecode.decode(JsonWebsocket.self, from: json)
print(output.data)
}
catch let error{
print(error.localizedDescription)
}
alter native
otherwise, create a custom
struct JsonWebsocket: Decodable {
let exchange: String
let avgp: String
let mcap: String
let ppc7D: String
let ppc12h: String
let ppc4h: String
let ppc24h: String
init(json: [String]) {
self.exchange = json[0]
self.avgp = json[1]
self.mcap = json[2]
self.ppc7D = json[3]
self.ppc12h = json[4]
self.ppc4h = json[5]
self.ppc24h = json[6]
}
}
do {
let jsonData = try JSONSerialization.jsonObject(with: json, options: []) as? [String: Any]
var jsonWebsocket: [JsonWebsocket] = []
if let data = jsonData!["data"] as? [[String]] {
for d in data {
jsonWebsocket.append(JsonWebsocket(json: d))
}
}
print(jsonWebsocket.count)
}
catch let error{
print(error.localizedDescription)
}
I am trying to parse my json data in swift 3.0. I am using Alamofire 4.0+
Here is my json
{
"token":
"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE1MDQ0MjgzNzgxMTF9.CNonyvtQbRgaqqkdPO5KwqpVaUmlGrpaTqlBxmvaX80",
"expires": 1504428378111,
"user":
[{"user_id":13,"user_first_name":"Himanshu","user_last_name":"Srivastava","full_name":"Himanshu Srivastava"}]
}
Here is my model class to hold these values
import Foundation
import ObjectMapper
class LoginResult:Mappable{
var token:String?
var expires:Double?
var users:[[String:Any]]?
required init?(map:Map){
}
func mapping(map:Map)->Void{
self.token <- map["token"]
self.expires <- map["expires"]
self.users <- map["user"]
}
}
None of the solution available on internet worked for me. How can I parse this json and map to the model class?
Any help here?
I was mistaken, the value for key user is indeed a regular array.
This is a solution without a third party mapper and with an extra User struct (by the way the value for key expires is an Int rather than Double).
Assuming the user data comes from a database which always sends all fields the user keys are forced unwrapped. If this is not the case use optional binding also for the user data:
struct User {
let firstName : String
let lastName : String
let fullName : String
let userID : Int
}
class LoginResult {
let token : String
let expires : Int
var users = [User]()
init(json : [String:Any]) {
self.token = json["token"] as? String ?? ""
self.expires = json["expires"] as? Int ?? 0
if let users = json["user"] as? [[String:Any]] {
self.users = users.map { User(firstName: $0["user_first_name"] as! String,
lastName: $0["user_last_name"] as! String,
fullName: $0["full_name"] as! String,
userID: $0["user_id"] as! Int)
}
}
}
}
let json = "{\"token\":\"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE1MDQ0MjgzNzgxMTF9.CNonyvtQbRgaqqkdPO5KwqpVaUmlGrpaTqlBxmvaX80\",\"expires\":504428378111,\"user\":[{\"user_id\":13,\"user_first_name\":\"Himanshu\",\"user_last_name\":\"Srivastava\",\"full_name\":\"Himanshu Srivastava\"}]}"
let jsonData = json.data(using: .utf8)!
do {
if let userData = try JSONSerialization.jsonObject(with: jsonData) as? [String:Any] {
let loginResult = LoginResult(json: userData)
print(loginResult.users[0])
// do something with loginResult
}
} catch {
print(error)
}
Here is the answer with map replaced by dictionary. Don't forget to handle error or unwrap carefully :)
let str = "{\"token\": \"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE1MDQ0MjgzNzgxMTF9.CNonyvtQbRgaqqkdPO5KwqpVaUmlGrpaTqlBxmvaX80\",\"expires\": 1504428378111,\"user\": [{\"user_id\":13,\"user_first_name\":\"Himanshu\",\"user_last_name\":\"Srivastava\",\"full_name\":\"Himanshu Srivastava\"}]}"
let data = str.data(using: .utf8)
do{
let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? [String: Any]
//Pass this json into the following function
}catch let error{
}
func mapping(json:[String: Any]?)->Void{
self.token <- json?["token"] as? String
self.expires <- json?["expires"] as? Double
self.users <- json?["user"] as? [[String: Any]]
}
I'm trying to build a login function (POST method) and the resultant is a JSON with user details and few other details. I have created a class with all the fields I need to use from the result of POST call. But I'm facing an issue with deserialzing the json to the object of the class. Can some one help me with this. (I have seen similar questions on SO and tried solving using the solution. I have tried converting the json to string and then to swift object using var UserDetails = UserDetails(json:jsonString)
)
My code:
class UserDetails {
let token:String
let agent_id: Int
let user_id:Int
let company_id:Int
let affliate_Id:Int
let role_id:Int
let username: String
let surname:String
let lastname:String
init(token:String,agent_id: Int,user_id:Int,company_id:Int,affliate_Id:Int,role_id:Int,username: String,surname:String,lastname:String) {
self.token = token;
self.agent_id = agent_id;
self.user_id = user_id;
self.company_id = company_id;
self.affliate_Id = affliate_Id;
self.role_id = role_id;
self.username = username;
self.surname = surname;
self.lastname = lastname;
} }
My controller class:
let task = session.dataTask(with: request as URLRequest) { data, response, error in
guard data != nil else {
print("no data found: \(error)")
return
}
do {
if let json = try JSONSerialization.jsonObject(with: data!, options: []) as? NSDictionary {
NSLog("Login SUCCESS");
let prefs:UserDefaults = UserDefaults.standard
prefs.set(username, forKey: "USERNAME")
prefs.set(udid, forKey: "UDID")
prefs.synchronize()
print("Response: \(json)")
//var jsonString = NSString(data: json, encoding: String.Encoding.utf8)! as String
//when I tried to do the above statement, an error is thrown. Cannot convert value of type NSDictionary to expected argument type Data
//var person:UserDetails = UserDetails(json: jsonString)
self.dismiss(animated: true, completion: nil)
} else {
let jsonStr = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)// No error thrown, but not NSDictionary
print("Error could not parse JSON: \(jsonStr)")
}
} catch let parseError {
print(parseError)// Log the error thrown by `JSONObjectWithData`
let jsonStr = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)
print("Error could not parse JSON: '\(jsonStr)'")
}
}
task.resume()
JSON Response:
{
"user": {
"token": "ABCDEFGHI",
"agent_id": 0,
"user_id": 151,
"company_id": 1,
"affiliate_Id": 0,
"role_id": 1,
"username": "testman1",
"surname": "Test",
"lastname": "man",
},
"menu": [
{ .....
Can someone help me in solving this. Tia
You should avoid using Foundation classes (NSDictionary etc) and use Swift types.
I also suggest you add a failable initialiser to your UserDetails class that accepts a dictionary:
class UserDetails {
let token: String
let agentId: Int
let userId: Int
let companyId: Int
let affliateId: Int
let roleId: Int
let username: String
let surname: String
let lastname: String
init?(dictionary: [String:Any]) {
guard let token = dictionary["token"] as? String,
let agentId = dictionary["agent_id"] as? Int,
let userId = dictionary["user_id"] as? Int,
... // And so on
else {
return nil
}
self.token = token;
self.agentId = agentId;
self.userId = userId;
self.companyId = companyId;
self.affliateId = affliateId;
self.roleId = roleId;
self.username = username;
self.surname = surname;
self.lastname = lastname;
}
}
and in your completion block:
do {
if let json = try JSONSerialization.jsonObject(with: data!, options: []) as? [String:Any] {
if let userDict = json["user"] as [String:Any] {
guard let userObject = UserDetails(dictionary:userDict) else {
print("Failed to create user from dictionary")
return
}
// Do something with userObject
}
}
} catch let parseError {
I also took the liberty of removing the _ from your properties because _ are icky
First of all you need to use Swift native Dictionary instead of NSDictionary also batter if you define your init method of UserDetails with single parameter of type [String: Any].
class UserDetails {
var token:String = ""
var agent_id: Int = 0
var user_id:Int = 0
var company_id:Int = 0
var affliate_Id:Int = 0
var role_id:Int = 0
var username: String = ""
var surname:String = ""
var lastname:String = ""
init(userDic: [String: Any]) {
if let token = user["token"] as? String, let agent_id = user["agent_id"] as? Int,
let user_id = user["user_id"] as? Int, let company_id = user["company_id"] as? Int,
let affliate_Id = user["affliate_Id"] as? Int, let role_id = user["role_id"] as? Int,
let username = user["username"] as? String, let surname = user["surname"] as? String,
let lastname = user["lastname"] as? String {
self.token = token;
self.agent_id = agent_id;
self.user_id = user_id;
self.company_id = company_id;
self.affliate_Id = affliate_Id;
self.role_id = role_id;
self.username = username;
self.surname = surname;
self.lastname = lastname;
}
}
}
Now simply call this init method from your json response like this.
if let json = try JSONSerialization.jsonObject(with: data!, options: []) as? [String: Any], let userDic = json["user"] as? [String: Any]{
let userDetails = UserDetails(userDic: userDic)
}
Has anyone been able to find a way to parse through JSON files in Swift 3? I have been able to get the data to return but I am unsuccessful when it comes to breaking the data down into specific fields. I would post sample code but I've gone through so many different methods unsuccessfully and haven't saved any. The basic format I want to parse through is something like this. Thanks in advance.
{
"Language": {
"Field":[
{
"Number":"976",
"Name":"Test"
},
{
"Number":"977",
"Name":"Test"
}
]
}
}
Have you tried JSONSerialization.jsonObject(with:options:)?
var jsonString = "{" +
"\"Language\": {" +
"\"Field\":[" +
"{" +
"\"Number\":\"976\"," +
"\"Name\":\"Test\"" +
"}," +
"{" +
"\"Number\":\"977\"," +
"\"Name\":\"Test\"" +
"}" +
"]" +
"}" +
"}"
var data = jsonString.data(using: .utf8)!
let json = try? JSONSerialization.jsonObject(with: data)
Swift sometimes produces some very odd syntax.
if let number = json?["Language"]??["Field"]??[0]?["Number"] as? String {
print(number)
}
Everything in the JSON object hierarchy ends up getting wrapped as an optional (ie. AnyObject?). Array<T> subscript returns a non-optional T. For this JSON, which is wrapped in an optional, array subscript returns Optional<AnyObject>. However, Dictionary<K, V> subscript returns an Optional<V>. For this JSON, subscript returns the very odd looking
Optional<Optional<AnyObject>> (ie. AnyObject??).
json is an Optional<AnyObject>.
json?["Language"] returns an Optional<Optional<AnyObject>>.
json?["Language"]??["Field"] returns an Optional<Optional<AnyObject>>.
json?["Language"]??["Field"]??[0] returns an Optional<AnyObject>.
json?["Language"]??["Field"]??[0]?["Number"] returns an Optional<Optional<AnyObject>>.
json?["Language"]??["Field"]??[0]?["Number"] as? String returns an Optional<String>.
The Optional<String> is then used by the if let syntax to product a String.
Final note: iterating the field array looks like this.
for field in json?["Language"]??["Field"] as? [AnyObject] ?? [] {
if let number = field["Number"] as? String {
print(number)
}
}
Swift 4 Update
Swift 4 makes this all much easier to deal with. Again we will start with your test data (""" makes this so much nicer).
let data = """
{
"Language": {
"Field":[
{
"Number":"976",
"Name":"Test"
},
{
"Number":"977",
"Name":"Test"
}
]
}
}
""".data(using: .utf8)!
Next we can define classes around the objects used in your JSON.
struct Object: Decodable {
let language: Language
enum CodingKeys: String, CodingKey { case language="Language" }
}
struct Language: Decodable {
let fields: [Field]
enum CodingKeys: String, CodingKey { case fields="Field" }
}
struct Field: Decodable {
let number: String
let name: String
enum CodingKeys: String, CodingKey { case number="Number"; case name="Name" }
}
The CodingKeys enum is how struct properties are mapped to JSON object member strings. This mapping is done automagically by Decodable.
Parsing the JSON now is simple.
let object = try! JSONDecoder().decode(Object.self, from: data)
print(object.language.fields[0].name)
for field in object.language.fields {
print(field.number)
}
In Xcode 8 and Swift 3 id now imports as Any rather than AnyObject
This means that JSONSerialization.jsonObject(with: data) returns Any. So you have to cast the json data to a specific type like [String:Any]. Same applies to the next fields down the json.
var jsonString = "{" +
"\"Language\": {" +
"\"Field\":[" +
"{" +
"\"Number\":\"976\"," +
"\"Name\":\"Test1\"" +
"}," +
"{" +
"\"Number\":\"977\"," +
"\"Name\":\"Test2\"" +
"}" +
"]" +
"}" +
"}"
var data = jsonString.data(using: .utf8)!
if let parsedData = try? JSONSerialization.jsonObject(with: data) as! [String:Any] {
let language = parsedData["Language"] as! [String:Any]
print(language)
let field = language["Field"] as! [[String:Any]]
let name = field[0]["Name"]!
print(name) // ==> Test1
}
In practice you would probably want some specific field buried in the json. Lets assume it's the Name field of the first element of Field array. You can use a chain of unwraps like this to safely access the field:
var data = jsonString.data(using: .utf8)!
if let json = try? JSONSerialization.jsonObject(with: data) as? [String:Any],
let language = json?["Language"] as? [String:Any],
let field = language["Field"] as? [[String:Any]],
let name = field[0]["Name"] as? String, field.count > 0 {
print(name) // ==> Test1
} else {
print("bad json - do some recovery")
}
Also you may want to check Apple's Swift Blog Working with JSON in Swift
Shoving JSON into a string manually is a pita. Why don't you just put the JSON into a file and read that in?
Swift 3:
let bundle = Bundle(for: type(of: self))
if let theURL = bundle.url(forResource: "response", withExtension: "json") {
do {
let data = try Data(contentsOf: theURL)
if let parsedData = try? JSONSerialization.jsonObject(with: data) as! [String:Any] {
grok(parsedData)
}
} catch {
print(error)
}
}
override func viewDidLoad() {
super.viewDidLoad()
let url=URL(string:"http://api.androidhive.info/contacts/")
do {
let allContactsData = try Data(contentsOf: url!)
let allContacts = try JSONSerialization.jsonObject(with: allContactsData, options: JSONSerialization.ReadingOptions.allowFragments) as! [String : AnyObject]
if let arrJSON = allContacts["contacts"] {
for index in 0...arrJSON.count-1 {
let aObject = arrJSON[index] as! [String : AnyObject]
names.append(aObject["name"] as! String)
contacts.append(aObject["email"] as! String)
}
}
print(names)
print(contacts)
self.tableView.reloadData()
}
catch {
}
}
JSON Parsing in swift 4 using Decodable Protocol :
I create a mocky file using your json object :
http://www.mocky.io/v2/5a280c282f0000f92c0635e6
Here is the code to parse the JSON :
Model Creation :
import UIKit
struct Item : Decodable {
// Properties must be the same name as specified in JSON , else it will return nil
var Number : String
var Name : String
}
struct Language : Decodable {
var Field : [Item]
}
struct Result : Decodable {
var Language : Language
}
You can use optional in the model if you are uncertain that something might be missing in JSON file.
This is the parsing Logic :
class ViewController: UIViewController {
let url = "http://www.mocky.io/v2/5a280c282f0000f92c0635e6"
private func parseJSON() {
guard let url = URL(string: url) else { return }
let session = URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let data = data else { return }
guard let result = try? JSONDecoder().decode(Result.self, from: data) else { return }
print("\n\nResult : \(result)")
}
session.resume()
}
override func viewDidLoad() {
super.viewDidLoad()
parseJSON()
}
}
The Print Output :
Result : Result(Language: JSON_Parsing.Language(Field: [JSON_Parsing.Item(Number: "976", Name: "Test"), JSON_Parsing.Item(Number: "977", Name: "Test")]))
This the github Project link. You can check.
JSON Parsing using Swift 4 in Simple WAY
let url = URL(string: "http://mobileappdevelop.co/TIPIT/webservice/get_my_groups?user_id=5")
URLSession.shared.dataTask(with:url!, completionHandler: {(data, response, error) in
guard let data = data, error == nil else { return }
do {
let json = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String:Any]
print(json)
let posts = json["Field"] as? [[String: Any]] ?? []
print(posts)
} catch let error as NSError {
print(error)
}
}).resume()
}
Use SwiftJson library. I think its very easy way to parse.
let count: Int? = json["Field"].array?.count
if let ct = count {
for index in 0...ct-1{
let number = json ["Field"][index]["number"].string
let name = json ["Field"][index]["name"].string
....
like this .
dict = {
message = "Login successfully.";
status = 1;
"user_details" = (
{
dob = "1900-11-18";
email = "rizwan#gmail.com";
gender = male;
name = Rizwan;
nickname = Shaikh;
"profile_pic" = "1483434421.jpeg";
"social_id" = "<null>";
"user_id" = 2;
}
);
}
We can parse above json in Swift 3 as
var dict2 = dict as! [String : Any]
print(dict);
let demoStr = dict2["message"] as! String
print(demoStr)
let demoArray = dict2["user_details"] as! [Any]
let demoDict = demoArray[0] as! [String:Any]
print(demoDict["dob"]!)
I'm trying to parse a json but I have some difficulties with the data types and notably the AnyObject type + downcasting.
Let's consider the following json (it's an extract of a full json).
{ "weather":
[
{
"id":804,
"main":"Clouds",
"description":"overcast clouds",
"icon":"04d"
}
],
}
To me, the json can be described as follow :
- json: Dictionary of type [String: AnyObject] (or NSDictionary, so = [NSObject, AnyObject] in Xcode 6 b3)
- "weather": Array of type [AnyObject] (or NSArray)
- Dictionary of type [String: AnyObject] (or NSDictionary, so = [NSObject, AnyObject] in Xcode 6 b3)
My json is of type AnyObject! (I use JSONObjectWithData to get the JSON from a URL).
I then want to access the weather Dictionary. Here is the code I wrote.
var localError: NSError?
var json: AnyObject! = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &localError)
if let dict = json as? [String: AnyObject] {
if let weatherDictionary = dict["weather"] as? [AnyObject] {
// Do stuff with the weatherDictionary
}
}
Here is the error I got
Playground execution failed: error: <EXPR>:28:56: error: '[AnyObject]' is not a subtype of '(String, AnyObject)'
if let weatherDictionary = dict["weather"] as? [AnyObject] {
I don't understand why dict["weather"] is compared to a subtype of (String, AnyObject) and not AnyObject.
I declared my dictionary as [String: AnyObject], so I i access a value using the String key, I should have an AnyObject, no ?
If I use NSDictionary instead of [String: AnyObject], it works.
If I use NSArray instead of [AnyObject], it works.
- The Xcode 6 beta 3 release notes tell that "NSDictionary* is now imported from Objective-C APIs as [NSObject : AnyObject].".
- And the Swift book: "When you bridge from an NSArray object to a Swift array, the resulting array is of type [AnyObject]."
EDIT
I forgot to force unwrapping the dict["weather"]!.
if let dict = json as? [String: AnyObject] {
println(dict)
if let weatherDictionary = dict["weather"]! as? [AnyObject] {
println("\nWeather dictionary:\n\n\(weatherDictionary)")
if let descriptionString = weatherDictionary[0]["description"]! as? String {
println("\nDescription of the weather is: \(descriptionString)")
}
}
}
Note that we should double check for the existence of the first Optional.
if let dict = json as? [String: AnyObject] {
for key in ["weather", "traffic"] {
if let dictValue = dict[key] {
if let subArray = dictValue as? [AnyObject] {
println(subArray[0])
}
} else {
println("Key '\(key)' not found")
}
}
}
This works fine for me in the playground and in the terminal using env xcrun swift
UPDATED FOR SWIFT 4 AND CODABLE
Here is a Swift 4 example using the Codable protocol.
var jsonStr = "{\"weather\":[{\"id\":804,\"main\":\"Clouds\",\"description\":\"overcast clouds\",\"icon\":\"04d\"}],}"
struct Weather: Codable {
let id: Int
let main: String
let description: String
let icon: String
}
struct Result: Codable {
let weather: [Weather]
}
do {
let weather = try JSONDecoder().decode(Result.self, from: jsonStr.data(using: .utf8)!)
print(weather)
}
catch {
print(error)
}
UPDATED FOR SWIFT 3.0
I have updated the code for Swift 3 and also showed how to wrap the parsed JSON into objects. Thanks for all the up votes!
import Foundation
struct Weather {
let id: Int
let main: String
let description: String
let icon: String
}
extension Weather {
init?(json: [String: Any]) {
guard
let id = json["id"] as? Int,
let main = json["main"] as? String,
let description = json["description"] as? String,
let icon = json["icon"] as? String
else { return nil }
self.id = id
self.main = main
self.description = description
self.icon = icon
}
}
var jsonStr = "{\"weather\":[{\"id\":804,\"main\":\"Clouds\",\"description\":\"overcast clouds\",\"icon\":\"04d\"}],}"
enum JSONParseError: Error {
case notADictionary
case missingWeatherObjects
}
var data = jsonStr.data(using: String.Encoding.ascii, allowLossyConversion: false)
do {
var json = try JSONSerialization.jsonObject(with: data!, options: [])
guard let dict = json as? [String: Any] else { throw JSONParseError.notADictionary }
guard let weatherJSON = dict["weather"] as? [[String: Any]] else { throw JSONParseError.missingWeatherObjects }
let weather = weatherJSON.flatMap(Weather.init)
print(weather)
}
catch {
print(error)
}
-- Previous Answer --
import Foundation
var jsonStr = "{\"weather\":[{\"id\":804,\"main\":\"Clouds\",\"description\":\"overcast clouds\",\"icon\":\"04d\"}],}"
var data = jsonStr.dataUsingEncoding(NSASCIIStringEncoding, allowLossyConversion: false)
var localError: NSError?
var json: AnyObject! = NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers, error: &localError)
if let dict = json as? [String: AnyObject] {
if let weather = dict["weather"] as? [AnyObject] {
for dict2 in weather {
let id = dict2["id"]
let main = dict2["main"]
let description = dict2["description"]
println(id)
println(main)
println(description)
}
}
}
Since I'm still getting up-votes for this answer, I figured I would revisit it for Swift 2.0:
import Foundation
var jsonStr = "{\"weather\":[{\"id\":804,\"main\":\"Clouds\",\"description\":\"overcast clouds\",\"icon\":\"04d\"}],}"
var data = jsonStr.dataUsingEncoding(NSASCIIStringEncoding, allowLossyConversion: false)
do {
var json = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers)
if let dict = json as? [String: AnyObject] {
if let weather = dict["weather"] as? [AnyObject] {
for dict2 in weather {
let id = dict2["id"] as? Int
let main = dict2["main"] as? String
let description = dict2["description"] as? String
print(id)
print(main)
print(description)
}
}
}
}
catch {
print(error)
}
The biggest difference is that the variable json is no longer an optional type and the do/try/catch syntax. I also went ahead and typed id, main, and description.
Try:
https://github.com/dankogai/swift-json
With it you can go like this:
let obj:[String:AnyObject] = [
"array": [JSON.null, false, 0, "", [], [:]],
"object":[
"null": JSON.null,
"bool": true,
"int": 42,
"double": 3.141592653589793,
"string": "a α\t弾\n𪚲",
"array": [],
"object": [:]
],
"url":"http://blog.livedoor.com/dankogai/"
]
let json = JSON(obj)
json.toString()
json["object"]["null"].asNull // NSNull()
json["object"]["bool"].asBool // true
json["object"]["int"].asInt // 42
json["object"]["double"].asDouble // 3.141592653589793
json["object"]["string"].asString // "a α\t弾\n𪚲"
json["array"][0].asNull // NSNull()
json["array"][1].asBool // false
json["array"][2].asInt // 0
json["array"][3].asString // ""
Using my library (https://github.com/isair/JSONHelper) you can do this with your json variable of type AnyObject:
var weathers = [Weather]() // If deserialization fails, JSONHelper just keeps the old value in a non-optional variable. This lets you assign default values like this.
if let jsonDictionary = json as? JSONDictionary { // JSONDictionary is an alias for [String: AnyObject]
weathers <-- jsonDictionary["weather"]
}
Had your array not been under the key "weather", your code would have been just this:
var weathers = [Weather]()
weathers <-- json
Or if you have a json string in your hands you can just pass it as well, instead of creating a JSON dictionary from the string first. The only setup you need to do is writing a Weather class or struct:
struct Weather: Deserializable {
var id: String?
var name: String?
var description: String?
var icon: String?
init(data: [String: AnyObject]) {
id <-- data["id"]
name <-- data["name"]
description <-- data["description"]
icon <-- data["icon"]
}
}