I'm trying to parse a json string:
if let jsonStr = asd.value(forKey: "orderData") as? String {
print(jsonStr)
let data = jsonStr.data(using: String.Encoding.utf8, allowLossyConversion: false)!
do {
let json = try JSONSerialization.jsonObject(with: data, options: []) as! [String: AnyObject] // CRASHES HERE
if let names = json["product_name"] as? [String] {
print(names)
}
} catch let error as NSError {
print("Failed to load: \(error.localizedDescription)")
}
}
But at the line let json = try JSONSeri... it crashes saying Could not cast value of type '__NSArrayI' to 'NSDictionary'.
Also tried changing this as! [String: AnyObject] to as! [[String: AnyObject]]. But it still doesn't work.
This is my json string structure:
[
{
"product_id" : "1",
"category_json" : {
"category_id" : "1",
"category_name" : "nvm"
},
"selling_price" : "200",
"product_name" : "nvm",
},
{
"product_id" : "2",
"category_json" : {
"category_id" : "2",
"category_name" : "cas"
},
"selling_price" : "800",
"product_name" : "cas",
}
]
You should not be force casting with ! unless you are 100% sure that it will succeed.
I would suggest you use the following:
let jsonArray = try? JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [[String: Any]]
This will return you a list of products. If you want a list of the product names than you need to iterate over it and extract the product name of each item. You can do this like so:
let names = jsonArray.map({ $0["product_name"] as? String })
As already mentioned the object is an array, you have to use a for loop to get all items
...
let data = Data(jsonStr.utf8)
do {
if let json = try JSONSerialization.jsonObject(with: data) as? [[String: Any]] {
for item in json {
if let name = item["product_name"] as? String {
print(name)
}
}
}
} catch {
print("Failed to load: \(error.localizedDescription)")
}
I need to take the value "maxtemp_c" from the json request, but it didn't work.
This is what I've do, It will block when I try to parse the json and the value is nil
//url of the json
let url = URL(string: "http://api.apixu.com/v1/forecast.json?key=6cffef39633d4489a0e101339171811&q=Loria&days=3")!
let taskfor = URLSession.shared.dataTask(with: url) { (data, response, error) in
if error != nil {
print("some error occured")
} else {
if error == nil {
do{
let jsonResult = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as! [String : AnyObject]
let forecast = jsonResult["forecast"] as? [String : AnyObject]
// I would not recommend to use NSDictionary, try using Swift types instead
guard let forecastday = forecast!["forecastday"] as? [[String:Any]] else { return }
// Check for the weather parameter as an array of dictionaries and than excess the first array's description
var finalArray:[Any] = []
//now I try to parse the json but the result is nil
for result in forecastday {
if let dict = result as? [String: Any], let forecastday = dict["day"] as? [String] {
finalArray.append(forecastday)
}
}
print(finalArray)
}catch {
print("JSON Preocessing failed")
}
}
}
}
taskfor.resume()
and this is the json that I have to parse
"forecast": {
"forecastday": [ //this is the problem that the value is nil
{
"date": "2017-11-26",
"date_epoch": 1511654400,
"day": {
"maxtemp_c": 7.3, //this is the value that I need
Looks like "day" key contains Dictionary not Array, just change it to [String: Any] from [String]
for result in forecastday {
if let dict = result as? [String: Any], let forecastday = dict["day"] as? [String: Any] {
finalArray.append(forecastday)
}
}
If you want just "maxtemp_c" array then declare final array as [Double] and add a check for "maxtemp_c" in the end
if let forecastday = forecast["forecastday"] as? [[String: Any]] {
var finalArray: [Double] = []
for result in forecastday {
if let dict = result as? [String: Any], let forecastday = dict["day"] as? [String: Any], let temp = forecastday["maxtemp_c"] as? Double {
finalArray.append(temp)
}
}
print(finalArray)
}
If you want "maxtemp_c" in [String] format then do
finalArray.append(String(format: "%.1f", temp))
{
"status": true,
"status_code": 1,
"content": [
{
"cat_id": "3",
"cat_name": "Food",
"cat_parentid": "2"
},
{
"cat_id": "4",
"cat_name": "Entertainment",
"cat_parentid": "2"
},
{
"cat_id": "5",
"cat_name": "Cars",
"cat_parentid": "2"
},
{
"cat_id": "12",
"cat_name": "Personal Care",
"cat_parentid": "2"
}
],
"message": "Success"
}
UPDATE
do {
//create json object from data
if let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String: Any] {
completion((json as? AnyObject)!) //here completion callback will return the jsonObject to my UIViewController.
}
} catch let error {
print(error.localizedDescription)
}
this is my JSONObject. I am very new to the swift. how to get the content JSONArray and further process in swift.? Anybody can help me? Help will be appreciated.
This code checks if the status is true, gets the array for key content and prints all values in the array.
The array is clearly [[String:String]] so cast the object to this specific type.
do {
//create json object from data
if let json = try JSONSerialization.jsonObject(with: data) as? [String: Any] {
if let status = json["status"] as? Bool, status == true {
if let content = json["content"] as? [[String:String]] {
for category in content {
let id = category["cat_id"]
let name = category["cat_name"]
let parentId = category["cat_parentid"]
print(id , name, parentId)
}
}
}
}
} catch let error {
print(error.localizedDescription)
}
PS: As always, never use .mutableContainers in Swift. It's meaningless
Check whether your json has content array
if let content = json["content"] as? [Dictionary<String, AnyObject>] {
print(content) // it will give you content array
}
Get content array like this:
let allContent = json["content"] as? [[String: Any]]
Full sample:
do {
//create json object from data
if let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String: Any] {
if let allContent = json["content"] as? [[String: Any]] {
for content in allContent {
let catId = content["cat_id"] as? String
let catName = content["cat_name"] as? String
let catParentId = content["cat_parentid"] as? String
print(">> catid=" + catId!)
print(">> catName=" + catName!)
print(">> catparentID=" + catParentId!)
}
}
}
} catch let error {
print(error.localizedDescription)
}
let content = dict.objectForKey("content")! as NSArray
Then you can get json of single object for parsing by
for var cat in content
{
print(cat)
}
Another alternative way, by using the library.
First, import JSON library for Swift - SwiftyJSON and use the code:
import SwiftyJSON
let json = JSON(<jsonObject data>)
let contentArray: Array<JSON> = json["content"].arrayValue
Library Integration
If you're using cocoapods then use this pod:
pod 'SwiftyJSON'
OR else just drag SwiftyJSON.swift to the project tree.
you can extract you data by providing key
if let array = result["content"] as? Array<AnyObject> {
print(arry)
}
You can access like below
if let filePath = Bundle.main.path(forResource: "sample", ofType: "json"), let data = FileManager().contents(atPath: filePath) {
do {
let dicRes = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [String: Any]
let contentArray = dicRes?["content"]
print("contentArray == \(contentArray)")
} catch {
}
}
I want to make one function in my swift project that converts String to Dictionary json format but I got one error:
Cannot convert expression's type (#lvalue NSData,options:IntegerLitralConvertible ...
This is my code:
func convertStringToDictionary (text:String) -> Dictionary<String,String> {
var data :NSData = text.dataUsingEncoding(NSUTF8StringEncoding)!
var json :Dictionary = NSJSONSerialization.JSONObjectWithData(data, options:0, error: nil)
return json
}
I make this function in Objective-C :
- (NSDictionary*)convertStringToDictionary:(NSString*)string {
NSError* error;
//giving error as it takes dic, array,etc only. not custom object.
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
id json = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
return json;
}
Warning: this is a convenience method to convert a JSON string to a dictionary if, for some reason, you have to work from a JSON string. But if you have the JSON data available, you should instead work with the data, without using a string at all.
Swift 3
func convertToDictionary(text: String) -> [String: Any]? {
if let data = text.data(using: .utf8) {
do {
return try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
} catch {
print(error.localizedDescription)
}
}
return nil
}
let str = "{\"name\":\"James\"}"
let dict = convertToDictionary(text: str)
Swift 2
func convertStringToDictionary(text: String) -> [String:AnyObject]? {
if let data = text.dataUsingEncoding(NSUTF8StringEncoding) {
do {
return try NSJSONSerialization.JSONObjectWithData(data, options: []) as? [String:AnyObject]
} catch let error as NSError {
print(error)
}
}
return nil
}
let str = "{\"name\":\"James\"}"
let result = convertStringToDictionary(str)
Original Swift 1 answer:
func convertStringToDictionary(text: String) -> [String:String]? {
if let data = text.dataUsingEncoding(NSUTF8StringEncoding) {
var error: NSError?
let json = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.allZeros, error: &error) as? [String:String]
if error != nil {
println(error)
}
return json
}
return nil
}
let str = "{\"name\":\"James\"}"
let result = convertStringToDictionary(str) // ["name": "James"]
if let name = result?["name"] { // The `?` is here because our `convertStringToDictionary` function returns an Optional
println(name) // "James"
}
In your version, you didn't pass the proper parameters to NSJSONSerialization and forgot to cast the result. Also, it's better to check for the possible error. Last note: this works only if your value is a String. If it could be another type, it would be better to declare the dictionary conversion like this:
let json = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.allZeros, error: &error) as? [String:AnyObject]
and of course you would also need to change the return type of the function:
func convertStringToDictionary(text: String) -> [String:AnyObject]? { ... }
I've updated Eric D's answer for Swift 5:
func convertStringToDictionary(text: String) -> [String:AnyObject]? {
if let data = text.data(using: .utf8) {
do {
let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String:AnyObject]
return json
} catch {
print("Something went wrong")
}
}
return nil
}
Swift 3:
if let data = text.data(using: String.Encoding.utf8) {
do {
let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String:Any]
print(json)
} catch {
print("Something went wrong")
}
}
With Swift 3, JSONSerialization has a method called jsonObject(with:options:). jsonObject(with:options:) has the following declaration:
class func jsonObject(with data: Data, options opt: JSONSerialization.ReadingOptions = []) throws -> Any
Returns a Foundation object from given JSON data.
When you use jsonObject(with:options:), you have to deal with error handling (try, try? or try!) and type casting (from Any). Therefore, you can solve your problem with one of the following patterns.
#1. Using a method that throws and returns a non-optional type
import Foundation
func convertToDictionary(from text: String) throws -> [String: String] {
guard let data = text.data(using: .utf8) else { return [:] }
let anyResult: Any = try JSONSerialization.jsonObject(with: data, options: [])
return anyResult as? [String: String] ?? [:]
}
Usage:
let string1 = "{\"City\":\"Paris\"}"
do {
let dictionary = try convertToDictionary(from: string1)
print(dictionary) // prints: ["City": "Paris"]
} catch {
print(error)
}
let string2 = "{\"Quantity\":100}"
do {
let dictionary = try convertToDictionary(from: string2)
print(dictionary) // prints [:]
} catch {
print(error)
}
let string3 = "{\"Object\"}"
do {
let dictionary = try convertToDictionary(from: string3)
print(dictionary)
} catch {
print(error) // prints: Error Domain=NSCocoaErrorDomain Code=3840 "No value for key in object around character 9." UserInfo={NSDebugDescription=No value for key in object around character 9.}
}
#2. Using a method that throws and returns an optional type
import Foundation
func convertToDictionary(from text: String) throws -> [String: String]? {
guard let data = text.data(using: .utf8) else { return [:] }
let anyResult: Any = try JSONSerialization.jsonObject(with: data, options: [])
return anyResult as? [String: String]
}
Usage:
let string1 = "{\"City\":\"Paris\"}"
do {
let dictionary = try convertToDictionary(from: string1)
print(String(describing: dictionary)) // prints: Optional(["City": "Paris"])
} catch {
print(error)
}
let string2 = "{\"Quantity\":100}"
do {
let dictionary = try convertToDictionary(from: string2)
print(String(describing: dictionary)) // prints nil
} catch {
print(error)
}
let string3 = "{\"Object\"}"
do {
let dictionary = try convertToDictionary(from: string3)
print(String(describing: dictionary))
} catch {
print(error) // prints: Error Domain=NSCocoaErrorDomain Code=3840 "No value for key in object around character 9." UserInfo={NSDebugDescription=No value for key in object around character 9.}
}
#3. Using a method that does not throw and returns a non-optional type
import Foundation
func convertToDictionary(from text: String) -> [String: String] {
guard let data = text.data(using: .utf8) else { return [:] }
let anyResult: Any? = try? JSONSerialization.jsonObject(with: data, options: [])
return anyResult as? [String: String] ?? [:]
}
Usage:
let string1 = "{\"City\":\"Paris\"}"
let dictionary1 = convertToDictionary(from: string1)
print(dictionary1) // prints: ["City": "Paris"]
let string2 = "{\"Quantity\":100}"
let dictionary2 = convertToDictionary(from: string2)
print(dictionary2) // prints: [:]
let string3 = "{\"Object\"}"
let dictionary3 = convertToDictionary(from: string3)
print(dictionary3) // prints: [:]
#4. Using a method that does not throw and returns an optional type
import Foundation
func convertToDictionary(from text: String) -> [String: String]? {
guard let data = text.data(using: .utf8) else { return nil }
let anyResult = try? JSONSerialization.jsonObject(with: data, options: [])
return anyResult as? [String: String]
}
Usage:
let string1 = "{\"City\":\"Paris\"}"
let dictionary1 = convertToDictionary(from: string1)
print(String(describing: dictionary1)) // prints: Optional(["City": "Paris"])
let string2 = "{\"Quantity\":100}"
let dictionary2 = convertToDictionary(from: string2)
print(String(describing: dictionary2)) // prints: nil
let string3 = "{\"Object\"}"
let dictionary3 = convertToDictionary(from: string3)
print(String(describing: dictionary3)) // prints: nil
Swift 5
extension String {
func convertToDictionary() -> [String: Any]? {
if let data = data(using: .utf8) {
return try? JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
}
return nil
}
}
Swift 4
extension String {
func convertToDictionary() -> [String: Any]? {
if let data = self.data(using: .utf8) {
do {
return try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
} catch {
print(error.localizedDescription)
}
}
return nil
}
}
Details
Xcode Version 10.3 (10G8), Swift 5
Solution
import Foundation
// MARK: - CastingError
struct CastingError: Error {
let fromType: Any.Type
let toType: Any.Type
init<FromType, ToType>(fromType: FromType.Type, toType: ToType.Type) {
self.fromType = fromType
self.toType = toType
}
}
extension CastingError: LocalizedError {
var localizedDescription: String { return "Can not cast from \(fromType) to \(toType)" }
}
extension CastingError: CustomStringConvertible { var description: String { return localizedDescription } }
// MARK: - Data cast extensions
extension Data {
func toDictionary(options: JSONSerialization.ReadingOptions = []) throws -> [String: Any] {
return try to(type: [String: Any].self, options: options)
}
func to<T>(type: T.Type, options: JSONSerialization.ReadingOptions = []) throws -> T {
guard let result = try JSONSerialization.jsonObject(with: self, options: options) as? T else {
throw CastingError(fromType: type, toType: T.self)
}
return result
}
}
// MARK: - String cast extensions
extension String {
func asJSON<T>(to type: T.Type, using encoding: String.Encoding = .utf8) throws -> T {
guard let data = data(using: encoding) else { throw CastingError(fromType: type, toType: T.self) }
return try data.to(type: T.self)
}
func asJSONToDictionary(using encoding: String.Encoding = .utf8) throws -> [String: Any] {
return try asJSON(to: [String: Any].self, using: encoding)
}
}
// MARK: - Dictionary cast extensions
extension Dictionary {
func toData(options: JSONSerialization.WritingOptions = []) throws -> Data {
return try JSONSerialization.data(withJSONObject: self, options: options)
}
}
Usage
let value1 = try? data.toDictionary()
let value2 = try? data.to(type: [String: Any].self)
let value3 = try? data.to(type: [String: String].self)
let value4 = try? string.asJSONToDictionary()
let value5 = try? string.asJSON(to: [String: String].self)
Test sample
Do not forget to paste the solution code here
func testDescriber(text: String, value: Any) {
print("\n//////////////////////////////////////////")
print("-- \(text)\n\n type: \(type(of: value))\n value: \(value)")
}
let json1: [String: Any] = ["key1" : 1, "key2": true, "key3" : ["a": 1, "b": 2], "key4": [1,2,3]]
var jsonData = try? json1.toData()
testDescriber(text: "Sample test of func toDictionary()", value: json1)
if let data = jsonData {
print(" Result: \(String(describing: try? data.toDictionary()))")
}
testDescriber(text: "Sample test of func to<T>() -> [String: Any]", value: json1)
if let data = jsonData {
print(" Result: \(String(describing: try? data.to(type: [String: Any].self)))")
}
testDescriber(text: "Sample test of func to<T>() -> [String] with cast error", value: json1)
if let data = jsonData {
do {
print(" Result: \(String(describing: try data.to(type: [String].self)))")
} catch {
print(" ERROR: \(error)")
}
}
let array = [1,4,5,6]
testDescriber(text: "Sample test of func to<T>() -> [Int]", value: array)
if let data = try? JSONSerialization.data(withJSONObject: array) {
print(" Result: \(String(describing: try? data.to(type: [Int].self)))")
}
let json2 = ["key1": "a", "key2": "b"]
testDescriber(text: "Sample test of func to<T>() -> [String: String]", value: json2)
if let data = try? JSONSerialization.data(withJSONObject: json2) {
print(" Result: \(String(describing: try? data.to(type: [String: String].self)))")
}
let jsonString = "{\"key1\": \"a\", \"key2\": \"b\"}"
testDescriber(text: "Sample test of func to<T>() -> [String: String]", value: jsonString)
print(" Result: \(String(describing: try? jsonString.asJSON(to: [String: String].self)))")
testDescriber(text: "Sample test of func to<T>() -> [String: String]", value: jsonString)
print(" Result: \(String(describing: try? jsonString.asJSONToDictionary()))")
let wrongJsonString = "{\"key1\": \"a\", \"key2\":}"
testDescriber(text: "Sample test of func to<T>() -> [String: String] with JSONSerialization error", value: jsonString)
do {
let json = try wrongJsonString.asJSON(to: [String: String].self)
print(" Result: \(String(describing: json))")
} catch {
print(" ERROR: \(error)")
}
Test log
//////////////////////////////////////////
-- Sample test of func toDictionary()
type: Dictionary<String, Any>
value: ["key4": [1, 2, 3], "key2": true, "key3": ["a": 1, "b": 2], "key1": 1]
Result: Optional(["key4": <__NSArrayI 0x600002a35380>(
1,
2,
3
)
, "key2": 1, "key3": {
a = 1;
b = 2;
}, "key1": 1])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: Any]
type: Dictionary<String, Any>
value: ["key4": [1, 2, 3], "key2": true, "key3": ["a": 1, "b": 2], "key1": 1]
Result: Optional(["key4": <__NSArrayI 0x600002a254d0>(
1,
2,
3
)
, "key2": 1, "key1": 1, "key3": {
a = 1;
b = 2;
}])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String] with cast error
type: Dictionary<String, Any>
value: ["key4": [1, 2, 3], "key2": true, "key3": ["a": 1, "b": 2], "key1": 1]
ERROR: Can not cast from Array<String> to Array<String>
//////////////////////////////////////////
-- Sample test of func to<T>() -> [Int]
type: Array<Int>
value: [1, 4, 5, 6]
Result: Optional([1, 4, 5, 6])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: String]
type: Dictionary<String, String>
value: ["key1": "a", "key2": "b"]
Result: Optional(["key1": "a", "key2": "b"])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: String]
type: String
value: {"key1": "a", "key2": "b"}
Result: Optional(["key1": "a", "key2": "b"])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: String]
type: String
value: {"key1": "a", "key2": "b"}
Result: Optional(["key1": a, "key2": b])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: String] with JSONSerialization error
type: String
value: {"key1": "a", "key2": "b"}
ERROR: Error Domain=NSCocoaErrorDomain Code=3840 "Invalid value around character 21." UserInfo={NSDebugDescription=Invalid value around character 21.}
I found code which converts the json string to NSDictionary or NSArray. Just add the extension.
SWIFT 3.0
HOW TO USE
let jsonData = (convertedJsonString as! String).parseJSONString
EXTENSION
extension String
{
var parseJSONString: AnyObject?
{
let data = self.data(using: String.Encoding.utf8, allowLossyConversion: false)
if let jsonData = data
{
// Will return an object or nil if JSON decoding fails
do
{
let message = try JSONSerialization.jsonObject(with: jsonData, options:.mutableContainers)
if let jsonResult = message as? NSMutableArray {
return jsonResult //Will return the json array output
} else if let jsonResult = message as? NSMutableDictionary {
return jsonResult //Will return the json dictionary output
} else {
return nil
}
}
catch let error as NSError
{
print("An error occurred: \(error)")
return nil
}
}
else
{
// Lossless conversion of the string was not possible
return nil
}
}
}
In 2022 year, I'm using JSONDecoder.
struct GroceryProduct: Codable {
var name: String
var points: Int
var description: String?
}
let json = """
{
"name": "Durian",
"points": 600,
"description": "A fruit with a distinctive scent."
}
""".data(using: .utf8)!
let decoder = JSONDecoder()
do {
let product = try decoder.decode(GroceryProduct.self, from: json)
}
catch { //error handle }
print(product.name) // Prints "Durian"
let JSONData = jsonString.data(using: .utf8)!
let jsonResult = try JSONSerialization.jsonObject(with: data, options: .mutableLeaves)
guard let userDictionary = jsonResult as? Dictionary<String, AnyObject> else {
throw NSError()}
I want to parsing my json file without "results" tab my new json file
[
{
"Id": 708,
"Name": "My name",
"ImageUrl": "2016728135316.jpg"
}
Codes under below
private func getMoviesFromJSON(jsonData: NSData) throws -> [Movie] {
var movies = [Movie]()
do {
if let jsonObject = try NSJSONSerialization.JSONObjectWithData(jsonData, options: .AllowFragments) as? [String: AnyObject], jsonArray = jsonObject["results"] as? [[String: AnyObject]] {
for i in jsonArray {
var properties = [String: AnyObject]()
properties[JSONKeys.id] = i[JSONKeys.id]
properties[JSONKeys.title] = i[JSONKeys.title]
properties[JSONKeys.posterPath] = i[JSONKeys.posterPath]
let movie = Movie(properties: properties)
movies.append(movie)
}
}
} catch {
throw TMDBErrors.ParsingError
}
return movies
}
I think must be change this line or must be delete.
jsonObject["results"]
I need your help , Thank You !
Your json doesn't have any results parameter .. so you don't need it at all ..
do {
if let jsonArray = try NSJSONSerialization.JSONObjectWithData(jsonData, options: .AllowFragments) as? [[String: AnyObject]] {
for i in jsonArray {
var properties = [String: AnyObject]()
properties[JSONKeys.id] = i[JSONKeys.id]
properties[JSONKeys.title] = i[JSONKeys.title]
properties[JSONKeys.posterPath] = i[JSONKeys.posterPath]
let movie = Movie(properties: properties)
movies.append(movie)
}
}
} catch {
throw TMDBErrors.ParsingError
}