golang recursively reflect both type of field and value

Question

In golang, I want to recursively reflect through a struct, getting the name of the field, it\'s type and the value.

The code here helped me reflect golang recurisive r

Answer 1

Try this:

func printValue(prefix string, v reflect.Value, visited map[interface{}]bool) {

    fmt.Printf("%s: ", v.Type())

    // Drill down through pointers and interfaces to get a value we can print.
    for v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface {
        if v.Kind() == reflect.Ptr {
            // Check for recursive data
            if visited[v.Interface()] {
                fmt.Println("visted")
                return
            }
            visited[v.Interface()] = true
        }
        v = v.Elem()
    }

    switch v.Kind() {
    case reflect.Slice, reflect.Array:
        fmt.Printf("%d elements\n", v.Len())
        for i := 0; i < v.Len(); i++ {
            fmt.Printf("%s%d: ", prefix, i)
            printValue(prefix+"   ", v.Index(i), visited)
        }
    case reflect.Struct:
        t := v.Type() // use type to get number and names of fields
        fmt.Printf("%d fields\n", t.NumField())
        for i := 0; i < t.NumField(); i++ {
            fmt.Printf("%s%s: ", prefix, t.Field(i).Name)
            printValue(prefix+"   ", v.Field(i), visited)
        }
    case reflect.Invalid:
        fmt.Printf("nil\n")
    default:
        fmt.Printf("%v\n", v.Interface())
    }
}

Because it's possible to get the type from a value, there's no need to pass types to the print function.

playground example