Parse json in Swift, AnyObject type

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 Foundationstruct 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 Foundationvar 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 Foundationvar 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       // truejson["object"]["int"].asInt         // 42json["object"]["double"].asDouble   // 3.141592653589793json["object"]["string"].asString   // "a α\t弾\n𪚲"json["array"][0].asNull             // NSNull()json["array"][1].asBool             // falsejson["array"][2].asInt              // 0json["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"]  }}