英文:
Extract tags from Go struct as a reflect.Value
问题
我正在尝试从一个名为Value的结构体中提取标签。我能够获取结构体的字段，但无法提取标签。我在这里做错了什么？我尝试了许多不同的方法（使用reflect.Type、interface{}等），但都失败了。
type House struct {Room stringHumans Human}type Human struct {Name string `anonymize:"true"` // 无法获取此标签Body stringTail string `anonymize:"true"` // 无法获取此标签}func printStructTags(f reflect.Value) { // f 是类型为`Human`的结构体for i := 0; i < f.NumField(); i++ {fmt.Printf("标签为 %s\n", reflect.TypeOf(f).Field(i).Tag) // 标签没有被打印出来}}
我将reflect.Value作为参数是因为这个函数是从另一个函数中以以下方式调用的：
var payload interface{}payload = &House{}// 设置完成v := reflect.ValueOf(payload).Elem()for j := 0; j < v.NumField(); j++ { // 遍历payload的所有字段f := v.Field(j)if f.Kind().String() == "struct" {printStructTags(f)}}
任何见解都将非常宝贵。
英文:
I'm trying to extract tags from a certain Value which is a struct. I am able to get the fields of the struct but unable to extract the tags. What am I doing wrong here? I've tried many different ways (using reflect.Type, interface{} etc) but all failed.
type House struct {Room stringHumans Human}type Human struct {Name string `anonymize:"true"` // Unable to get this tagBody stringTail string `anonymize:"true"` // Unable to get this tag}func printStructTags(f reflect.Value) { // f is of struct type `human`for i := 0; i < f.NumField(); i++ {fmt.Printf("Tags are %s\n", reflect.TypeOf(f).Field(i).Tag) // TAGS AREN'T PRINTED}}
The reason I use reflect.Value as the parameter is because this function is called from another function in the following manner
var payload interface{}payload = &House{}// Setup completev := reflect.ValueOf(payload).Elem()for j := 0; j < v.NumField(); j++ { // Go through all fields of payloadf := v.Field(j)if f.Kind().String() == "struct" {printStructTags(f)}}
Any insights would be extremely valuable
答案1
得分: 3
当你调用reflect.TypeOf(f)时，你会得到f的类型，它已经是一个reflect.Value。
使用f的Type()函数来获取类型并对其进行字段检查：
func printStructTags(f reflect.Value) { // f是结构体类型`human`for i := 0; i < f.NumField(); i++ {fmt.Printf("Tags are %s\n", f.Type().Field(i).Tag)}}
然而，更容易的方法是使用f.Type().Field(i).Tag.Get("anonymize")来检查标签并获取其值。这样你可以直接得到分配的值，例如在你的情况下是true，如果标签不存在则得到一个空字符串。
英文:
When you call reflect.TypeOf(f) you get the type of f, which is already a reflect.Value.
Use the Type() func of this f to get the type and do the Field check on it:
func printStructTags(f reflect.Value) { // f is of struct type `human`for i := 0; i < f.NumField(); i++ {fmt.Printf("Tags are %s\n", f.Type().Field(i).Tag)}}
However, it's easier to check for a tag and get its value with f.Type().Field(i).Tag.Get("anonymize"). This way you directly get the assigned value, for example true in your case and an empty string if the tag doesn't exist.
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