Golang打印结构总是报undefined

Question

这是我定义的结构 - 从 json 到 Go struct 工具生成：

type NYTimesNews struct {
    Data struct {
        LegacyCollection struct {
            CollectionsPage struct {
                Stream struct {
                    Edges []struct {
                        Node struct {
                            FirstPublished string `json:"firstPublished"`
                            Headline       struct {
                                Default string `json:"default"`
                            } `json:"headline"`
                            Summary string `json:"summary"`
                            URL     string `json:"url"`
                        } `json:"node"`
                    } `json:"edges"`
                } `json:"stream"`
            } `json:"collectionsPage"`
        } `json:"legacyCollection"`
    } `json:"data"`
}

当我在节点层迭代我的请求响应时，一切正常并且可以打印出来，下面是打印出边缘数组中所有节点的代码

  for i, Node:= range data.Data.LegacyCollection.CollectionsPage.Stream.Edges{
      // fmt.Printf("[%d] \n %s \n", i, Node)
      fmt.Printf("[%d] \n %s \n %s\n", i, reflect.TypeOf(Node),Node)
  }

输出

[0] 
 struct { Node struct { FirstPublished string "json:\"firstPublished\""; Headline struct { Default string "json:\"default\"" } "json:\"headline\""; Summary string "json:\"summary\""; URL string "json:\"url\"" } "json:\"node\"" } 
 {{2022-05-14T21:17:13.000Z {Turkey Offers to Evacuate Mariupol Fighters Despite Disagreements} Turkey has had a ship waiting for weeks in Istanbul to evacuate those remaining in the Azovstal steel plant, but Ukraine and Russia have not agreed to a plan, a Turkish official said. https://www.nytimes.com/2022/05/14/world/europe/azovstal-evacuation-turkey.html}}
[1] 
 struct { Node struct { FirstPublished string "json:\"firstPublished\""; Headline struct { Default string "json:\"default\"" } "json:\"headline\""; Summary string "json:\"summary\""; URL string "json:\"url\"" } "json:\"node\"" } 
 {{2022-05-14T16:26:03.000Z {Catalan Pop? Corsican Rock? It’s Europe’s Other Song Contest.} The Liet International, a competition for minority and regional languages, lacks the glitz of Eurovision. But its organizers say it helps keep endangered tongues alive. https://www.nytimes.com/2022/05/14/arts/music/minority-languages-song-contest.html}}

但是当我尝试访问节点结构中的单个字段时发生错误

修改后的代码：

  for i, Node:= range data.Data.LegacyCollection.CollectionsPage.Stream.Edges{
    fmt.Printf("[%d] \n %s \n %s -------- \n\n", i, reflect.TypeOf(Node), Node.FirstPublished)
    break
  }

输出

./getdata-url-nytimes.go:92:80: Node.FirstPublished 未定义（类型 struct{Node struct{FirstPublished string "json:"firstPublished" "; Headline struct{默认字符串 "json:"default""} "json:"headline""; 摘要字符串 "json:"summary""; URL string "json:"url""} "json:"node""} 没有字段或方法 FirstPublished)

当我使用 'doc fieldname' 打印 Go 结构中的字段时出现什么问题？

Answer 1

您将循环变量命名为 Node，但它真正包含的是类型 Edge 的结构。 .Node 是您迭代的集合中每个 Edge 的属性。您需要像这样通过边缘的 .Node 字段访问它：

  for i, edge:= range data.Data.LegacyCollection.CollectionsPage.Stream.Edges{
    fmt.Printf("[%d] \n %s \n %s -------- \n\n", i, reflect.TypeOf(edge.Node), edge.Node.FirstPublished)
    break
  }

Golang打印结构总是报undefined

Golang Print structure always report undefined

struct

go