JSON Deserialization in Swift

Question

After reading up a bit on collections, I began to wonder if json deserialization was going to be an issue given that collections need to specify a type for the values they contain. And in the case of dictionaries, one would need to specify the type for both the key and the value.

After a bit of experimentation, I found that the following works:

let jsonString = "{\"bool\": true, \"num\": 1,\"string\": \"a string\"}"
let jsonData = jsonString.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)

let json : AnyObject! = NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.MutableContainers, error: nil)

let valid = NSJSONSerialization.isValidJSONObject(json)

And when I use a playground (or am in the REPL), I get the following when printing out the contents of the json object:

["num": 1, "string": "a string", "bool": 1]

My question: is there may be a better way to handle this?

That's pretty much it, although I would tend to use optionals instead of implicitly unwrapped (? instead of !) And since it's a lot of arrays and dictionaries of AnyObject, there's a whole lot of casting going on. — David Berry
– David Berry, Commented Jun 8, 2014 at 19:02

Jean Le Moignan · Accepted Answer · 2015-05-22 14:01:35Z

1

I'd suggest typing your json object a little more:

let json = NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.MutableContainers, error: nil) as? Dictionary<String, AnyObject?>

This will help you access elements by their key.

edited May 22, 2015 at 14:01

answered Jun 8, 2014 at 20:27

Jean Le Moignan

22.2k3 gold badges33 silver badges37 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Jason G Over a year ago

Cannot conver the expression's type '$T4' to type 'Dictionary<String, AnyObject!>'

Collectives™ on Stack Overflow

JSON Deserialization in Swift

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related