Can Swift convert a class / struct data into dicti

问题:

For example:

class Test {
    var name: String;
    var age: Int;
    var height: Double;
    func convertToDict() -> [String: AnyObject] { ..... }
}

let test = Test();
test.name = "Alex";
test.age = 30;
test.height = 170;

let dict = test.convertToDict();

dict will have content:

{"name": "Alex", "age": 30, height: 170}

Is this possible in Swift?

And can I access a class like a dictionary, for example probably using:

test.value(forKey: "name");

Or something like that?

Thanks.

回答1:

You can just add a computed property to your struct to return a Dictionary with your values. Note that Swift native dictionary type doesn't have any method called value(forKey:). You would need to cast your Dictionary to NSDictionary:

struct Test {
    let name: String
    let age: Int
    let height: Double
    var dictionary: [String: Any] {
        return ["name": name,
                "age": age,
                "height": height]
    }
    var nsDictionary: NSDictionary {
        return dictionary as NSDictionary
    }
}

---

You can also extend Encodable protocol as suggested at the linked answer posted by @ColGraff to make it universal to all Encodable structs:

struct JSON {
    static let encoder = JSONEncoder()
}
extension Encodable {
    subscript(key: String) -> Any? {
        return dictionary[key]
    }
    var dictionary: [String: Any] {
        return (try? JSONSerialization.jsonObject(with: JSON.encoder.encode(self))) as? [String: Any] ?? [:]
    }
}

---

struct Test: Codable {
    let name: String
    let age: Int
    let height: Double
}

let test = Test(name: "Alex", age: 30, height: 170)
test["name"]    // Alex
test["age"]     // 30
test["height"]  // 170

回答2:

You could use Reflection and Mirror like this to make it more dynamic and ensure you do not forget a property.

struct Person {
  var name:String
  var position:Int
  var good : Bool
  var car : String

  var asDictionary : [String:Any] {
    let mirror = Mirror(reflecting: self)
    let dict = Dictionary(uniqueKeysWithValues: mirror.children.lazy.map({ (label:String?, value:Any) -> (String, Any)? in
      guard let label = label else { return nil }
      return (label, value)
    }).compactMap { $0 })
    return dict
  }
}


let p1 = Person(name: "Ryan", position: 2, good : true, car:"Ford")
print(p1.asDictionary)

["name": "Ryan", "position": 2, "good": true, "car": "Ford"]