如何在控制台中打印结构变量？

Question

How can I print (in the console) the Id, Title, Name, etc. of this struct in Golang?

type Project struct {
    Id int64 `json:"project_id"`
    Title string `json:"title"`
    Name string `json:"name"`
    Data Data `json:"data"`
    Commits Commits `json:"commits"`
}

转载于:https://stackoverflow.com/questions/24512112/how-to-print-struct-variables-in-console

Answer 1

To print the name of the fields in a struct:

fmt.Printf("%+v\n", yourProject)

From the fmt package:

when printing structs, the plus flag (%+v) adds field names

That supposes you have an instance of Project (in 'yourProject')

The article JSON and Go will give more details on how to retrieve the values from a JSON struct.

---

This Go by example page provides another technique:

type Response2 struct {
  Page   int      `json:"page"`
  Fruits []string `json:"fruits"`
}

res2D := &Response2{
    Page:   1,
    Fruits: []string{"apple", "peach", "pear"}}
res2B, _ := json.Marshal(res2D)
fmt.Println(string(res2B))

That would print:

{"Page":1,"Fruits":["apple","peach","pear"]}

---

If you don't have any instance, then you need to use reflection to display the name of the field of a given struct, as in this example.

type T struct {
    A int
    B string
}

t := T{23, "skidoo"}
s := reflect.ValueOf(&t).Elem()
typeOfT := s.Type()

for i := 0; i < s.NumField(); i++ {
    f := s.Field(i)
    fmt.Printf("%d: %s %s = %v\n", i,
        typeOfT.Field(i).Name, f.Type(), f.Interface())
}