在Swift 3中，如何将字典转换为Object? [英] In Swift 3, how to convert a dictionary to Object?

问题描述

[我是Swift的新手，我不知道这是否可能，所以请建议我]

[I am new to Swift, I don't know is this possible or not, so please suggest me]

我有一个这样的字典(动态的):

I have a dictionary (which is dynamic) like this:

let simpleHash = ["testA": "A", "testB": "B", "testC": "C"]

我想将其转换为对象，以便可以像这样访问:

I want to convert this to an Object, so that I can access like:

simpleHash.testA // instead of simpleHash["testA"]

我尝试了以下方法，但没有帮助

I have tried the below one, but it didn't help

let jsonData = try JSONSerialization.data(withJSONObject: simpleHash, options: .prettyPrinted)
let decoded = try JSONSerialization.jsonObject(with: jsonData, options: [])

有人可以在这方面建议我吗? 预先感谢！

Can anyone please suggest me on this. Thanks in advance!

推荐答案

Swift需要为testA明确声明一个变量，因此您将无法100％动态.但是，由于您需要在代码中使用该变量，因此在某些时候它是已知的.鉴于此，本着最小化声明约束的精神，您可以定义一个类，该类使用字典作为其内部存储，并将键值作为计算的属性公开.

Swift will need an explicitly declared variable for testA so you will not be able to be 100% dynamic. But, since you need to use the variable in code, it will be known at some point. Given this and in the spirit of minimizing the declaration constraints, you could define a class that uses the dictionary as its internal storage and exposes the key values as computed properties.

这是一个例子:

class DictionaryBased
{
   var content:[String:Any]
   init(_ dictionary:[String:Any])
   { content = dictionary }

   func get<T>(_ key:String, _ defaultValue:T) -> T 
   { return content[key] as? T ?? defaultValue }

   func set<T>(_ key:String, _ value:T)  
   { content[key] = value }
}

class SimpleHash:DictionaryBased 
{}

使用此功能，您可以根据需要使用扩展名添加计算的属性.

With this, you can add computed properties as needed (and where needed) using extensions.

extension SimpleHash
{
  var testA:String { get { return get("testA", "") }  set { set("testA",newValue) } }
  var testB:String { get { return get("testB", "") }  set { set("testB",newValue) } }

  // if variables are "read-only", you don't need the set { } part
  var testC:String { get { return get("testC", "") }  }
}

您可以添加键入或不键入并支持可选变量的变量，或者(如上所述)提供默认值.

You can add variables that are typed or not and support optionals or, (as above) provide default values.

extension SimpleHash
{
  var testD:Any?    { get { return get("testD", nil) }  set { set("testD",newValue) } }
  var testE:String? { get { return get("testE", nil) }  set { set("testE",newValue) } }
  var testF:Date?   { get { return get("testF", nil) }  set { set("testE",newValue) } }
}

要使用此基于字典的"对象，您需要在某个时候创建​​一个实例并为其提供字典的内容:

To use this "dictionary based" object, you would need to create an instance at some point and give it the dictionary's content:

let simpleHash = SimpleHash(["testA": "A", "testB": "B", "testC": "C"])

simpleHash.testA  // "A"
simpleHash.testD  // nil

请注意，这不会像使用本机属性并将字典映射到每个物理变量那样高效.另一方面，这样的代码要少得多.如果不经常引用变量，则为简单起见和灵活性，额外的开销可能是可以接受的折衷方案.

Note that, this isn't going to be as efficient as using native properties and mapping the dictionary to each physical variable. On the other hand, it is a lot less code so. If the variables are not referenced often, the extra overhead may be an acceptable trade off for simplicity and flexibility.

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