How to access deeply nested dictionaries in Swift

Question

I have a pretty complex data structure in my app, which I need to manipulate. I am trying to keep track of how many types of bugs a player has in thier garden. There are te

Answer 1

My primary use case was reading ad-hoc values from a deep dictionary. None of the answers given worked for me in my Swift 3.1 project, so I went looking and found Ole Begemann's excellent extension for Swift dictionaries, with a detailed explanation on how it works.

I've made a Github gist with the Swift file I made for using it, and I welcome feedback.

To use it, you can add the Keypath.swift into your project, and then you can simply use a keyPath subscript syntax on any [String:Any] dictionary as follows.

Considering you have a JSON object like so:

{
    "name":"John",
    "age":30,
    "cars": {
        "car1":"Ford",
        "car2":"BMW",
        "car3":"Fiat"
    }
}

stored in a dictionary var dict:[String:Any]. You could use the following syntax to get to the various depths of the object.

if let name = data[keyPath:"name"] as? String{
    // name has "John"
}
if let age = data[keyPath:"age"] as? Int{
    // age has 30
}
if let car1 = data[keyPath:"cars.car1"] as? String{
    // car1 has "Ford"
}

Note that the extension supports writing into nested dictionaries as well, but I haven't yet used this.

I still haven't found a way to access arrays within dictionary objects using this, but it's a start! I'm looking for a JSON Pointer implementation for Swift but haven't found one, yet.