CODEWITHSUNDEEP
reflectionstructgo
moesef
moesef

Reputation: 4841

Golang- Getting struct attribute name

I want to return the name of a struct attribute using the reflect package. So far I have:

type MultiQuestions struct {
    QuestionId      int64  
    QuestionType    string 
    QuestionText    string 
}
func (q *MultiQuestions) StructAttrName() string {
    return reflect.ValueOf(q).Elem().Field(0).Name
}

However, this gives me a error reflect.ValueOf(q).Elem().Field(0).Name undefined (type reflect.Value has no field or method Name)

I tried casting to StructField but that didn't work either. How do I get at the name of Struct?

In this case, the names I am interested in are QuestionId, QuestionType and QuestionText.

Upvotes: 6

Views: 8131

Answers (3)

VonC
VonC

Reputation: 1324537

You also can consider to utility functions defined in github.com/fatih/structure, like the Fields(s interface{}) []string one, which work on pointers or objects, including struct fields within the struct.

package main

import (
    "fmt"
    "reflect"

    "github.com/fatih/structure"
)

type MultiQuestions struct {
    QuestionId   int64
    QuestionType string
    QuestionText string
    SubMQ        SubMultiQuestions
}

type SubMultiQuestions struct{}

func (q *MultiQuestions) StructAttrName() string {
    return reflect.Indirect(reflect.ValueOf(q)).Type().Field(0).Name
}

func main() {
    fmt.Println((&MultiQuestions{}).StructAttrName())
    fmt.Println(Fields(&MultiQuestions{}))
    fmt.Println(Fields(MultiQuestions{}))
}

Output:

SubMQ
[QuestionId QuestionType QuestionText SubMQ]
[QuestionId QuestionType QuestionText SubMQ]

See a full example in this play.golang.org

Upvotes: 0

fabmilo
fabmilo

Reputation: 48330

Use the Type:

package main

import (
    "fmt"
    "reflect"
)

type MultiQuestions struct {
    QuestionId   int64
    QuestionType string
    QuestionText string
}

func (q *MultiQuestions) StructAttrName() string {
    return reflect.TypeOf(q).Elem().Field(0).Name
}

func main() {
    fmt.Println((&MultiQuestions{}).StructAttrName())
}

http://play.golang.org/p/su7VIKXBE2

Upvotes: 0

OneOfOne
OneOfOne

Reputation: 99234

You need to operate on the Type not the Value

func (q *MultiQuestions) StructAttrName() string {
    return reflect.Indirect(reflect.ValueOf(q)).Type().Field(0).Name
}

playground

Upvotes: 6

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