Trouble with nested Json data - json

Question

I'm having a ton of trouble trying to access the nested json data (pasted at the bottom). I'm able write:
var dataResults = jsonResult["data"] as NSDictionary
In order to create a dictionary containing the data within "data", however, Xcode will not allow me to call on anything within "data" such as the information within "current_condition". I've tried to make current_condition it's own dictionary like so:
var results = dataResults["current_condition"] as NSDictionary
But it would seem that this is turning up as nil
I have also attempted accessing using the standard method for calling nested loops:
var dataResults = jsonResult["data"]["current_condition"] as NSDictionary
But this results in a compiler error.
Any help? Much appreciated!
Json data:
{
data = {
"current_condition" = (
{
cloudcover = 0;
humidity = 68;
"observation_time" = "01:39 AM";
precipMM = "0.0";
pressure = 1017;
"temp_C" = 20;
"temp_F" = 68;
visibility = 10;
weatherCode = 143;
weatherDesc = (
{
value = Mist;
}
);
weatherIconUrl = (
{
value = "http://cdn.worldweatheronline.net/images/wsymbols01_png_64/wsymbol_0006_mist.png";
}
);
winddir16Point = NE;
winddirDegree = 50;
windspeedKmph = 7;
windspeedMiles = 4;
}
);
request = (
{
query = "London, United Kingdom";
type = City;
}
);
weather = (
{
date = "2014-07-25";
precipMM = "1.5";
tempMaxC = 27;
tempMaxF = 81;
tempMinC = 14;
tempMinF = 57;
weatherCode = 353;
weatherDesc = (
{
value = "Light rain shower";
}
);
weatherIconUrl = (
{
value = "http://cdn.worldweatheronline.net/images/wsymbols01_png_64/wsymbol_0009_light_rain_showers.png";
}
);
winddir16Point = NE;
winddirDegree = 54;
winddirection = NE;
windspeedKmph = 15;
windspeedMiles = 10;
},
{
date = "2014-07-26";
precipMM = "5.8";
tempMaxC = 28;
tempMaxF = 83;
tempMinC = 16;
tempMinF = 61;
weatherCode = 176;
weatherDesc = (
{
value = "Patchy rain nearby";
}
);
weatherIconUrl = (
{
value = "http://cdn.worldweatheronline.net/images/wsymbols01_png_64/wsymbol_0009_light_rain_showers.png";
}
);
winddir16Point = NNE;
winddirDegree = 12;
winddirection = NNE;
windspeedKmph = 11;
windspeedMiles = 7;
},
{
date = "2014-07-27";
precipMM = "0.2";
tempMaxC = 26;
tempMaxF = 80;
tempMinC = 13;
tempMinF = 55;
weatherCode = 116;
weatherDesc = (
{
value = "Partly Cloudy";
}
);
weatherIconUrl = (
{
value = "http://cdn.worldweatheronline.net/images/wsymbols01_png_64/wsymbol_0002_sunny_intervals.png";
}
);
winddir16Point = NW;
winddirDegree = 321;
winddirection = NW;
windspeedKmph = 14;
windspeedMiles = 9;
},
{
date = "2014-07-28";
precipMM = "1.9";
tempMaxC = 26;
tempMaxF = 78;
tempMinC = 12;
tempMinF = 54;
weatherCode = 116;
weatherDesc = (
{
value = "Partly Cloudy";
}
);
weatherIconUrl = (
{
value = "http://cdn.worldweatheronline.net/images/wsymbols01_png_64/wsymbol_0002_sunny_intervals.png";
}
);
winddir16Point = N;
winddirDegree = 351;
winddirection = N;
windspeedKmph = 13;
windspeedMiles = 8;
},
{
date = "2014-07-29";
precipMM = "0.0";
tempMaxC = 28;
tempMaxF = 82;
tempMinC = 16;
tempMinF = 60;
weatherCode = 113;
weatherDesc = (
{
value = Sunny;
}
);
weatherIconUrl = (
{
value = "http://cdn.worldweatheronline.net/images/wsymbols01_png_64/wsymbol_0001_sunny.png";
}
);
winddir16Point = NNW;
winddirDegree = 329;
winddirection = NNW;
windspeedKmph = 13;
windspeedMiles = 8;
}
);
};
}

Answer 1

Oddly enough, I have a sample weather app that I converted to Swift. I get my data elsewhere, but I found this library to be a great way to deal with JSON in Swift: https://github.com/dankogai/swift-json/. Much cleaner and easier.

Answer 2

It's because the subscript in Dictionary returns an optional:
subscript (key: KeyType) -> ValueType?
Meaning you have to unwrap the optional before you can downcast:
let dataResults = jsonResult["data"]! as NSDictionary
let results = dataResults["current_condition"]! as NSDictionary
As of Beta 3 you can access the value directly without downcasting, like this:
let dataResults = jsonResult["data"]!
let results = dataResults["current_condition"]
However I would suggest you wrap it around an if-let to make sure you don't unwrap nil values.