struct swift 的访问数据

Question

我试图在向 GPT3 open ai 端点发出发布请求后显示响应。

这是一个示例 JSON 响应：

{
    "id": "cmpl-4R7o3DcLSOGjjWHs5CrKXecNAoRDL",
    "object": "text_completion",
    "created": 1642370211,
    "model": "davinci:2020-05-03",
    "choices": [
        {
            "text": "\n\nA neutron star is a star that is so dense that it has collapsed into a sphere.\n\nA neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich",
            "index": 0,
            "logprobs": null,
            "finish_reason": "length"
        }
    ]
}

我特别想显示响应的文本。 为此，我根据https://app.quicktype.io/为普通类型返回的内容创建了两个结构。

struct Response: Codable, Identifiable{
    
    var id = String()
    var model = String()
    var choices: [Choice]
    
}

struct Choice: Codable{
    var finish_reason = String()
    var index = Int()
    var text = String()
    
}

然后我创建了一个 class 来调用端点，解码 JSON 并通过完成处理程序返回数据：

class GPT3TextComepletion: ObservableObject{
    
    @Published var response = Response.self

    
    func textCompletion(promptText:String, completion:@escaping  (Response) -> ()) {
        
        let token = "redacted"
        let url = URL(string: "https://api.openai.com/v1/engines/davinci/completions")!

        // prepare json data
        var json: [String: Any] = [
                                    "temperature": 0.7,
                                     "max_tokens": 60,
                                     "top_p": 1.0,
                                     "frequency_penalty": 0,
                                     "presence_penalty": 0]
        json["prompt"] = promptText

        let jsonData = try? JSONSerialization.data(withJSONObject: json)

        // create post request
        var request = URLRequest(url: url)
        request.httpMethod = "POST"

        // insert json data to the request
        request.httpBody = jsonData
        request.addValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addValue("application/json", forHTTPHeaderField: "Accept")
        request.setValue( "Bearer \(token)", forHTTPHeaderField: "Authorization")

        let task = URLSession.shared.dataTask(with: request) { data, response, error in
            guard let data = data, error == nil else {
                print(error?.localizedDescription ?? "No data")
                return
            }


            let response = try! JSONDecoder().decode(Response.self, from: data)
            let choice = response.choices
            print(choice)
            DispatchQueue.main.async {
                completion(response)
            }
        }
        task.resume()
    }
}

我可以通过以下方式访问不在选择数组中的任何数据，即 model：

    @State var response: Response? = nil
          Button(action: {GPT3TextComepletion().textCompletion(promptText: prompt, completion: {(response) in self.response = response })}) 
Text(response?.model ?? "some data")

但是我无法从选择结构中访问数据（我可以打印数据但不显示它）。 我收到的错误是：

Initializer 'init(_:)' requires that 'Choice' conform to 'StringProtocol'

由于 Choice 结构是一个数组，我尝试对其进行迭代但没有成功或访问数组的第三个元素：

 Text(response!.choices[2])

如果有人可以提供帮助，我想显示选择结构中的数据（特别是文本变量）。

谢谢！

Answer 1

Text(response!.choices[2])

此行返回一个不能表示字符串的 Choice 结构。 您需要更深一层 go 并访问它的文本属性。

Text(response!.choices[2].text)

我假设您为了示例的缘故已经硬编码并强制解包。 否则请遵循安全编码实践:)