JSON Parsing in Swift 3

Question

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 dat

Answer 1

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