reflect.FieldByIndex() Function in Golang with Examples
Go language provides inbuilt support implementation of run-time reflection and allowing a program to manipulate objects with arbitrary types with the help of reflect package. The reflect.FieldByIndex() Function in Golang is used to get the nested field corresponding to index. To access this function, one needs to imports the reflect package in the program.
Syntax:
func (v Value) FieldByIndex(index []int) Value
Parameters: This function accept only single parameters.
- index : This parameter is the []int type.
Return Value: This function returns the nested field corresponding to index.
Below examples illustrate the use of the above method in Golang:
Example 1:
package main
import (
"fmt"
"reflect"
)
func main() {
tt:= reflect.StructOf([]reflect.StructField{
{
Name: "Height" ,
Type: reflect.TypeOf(0.0),
Tag: `json: "height" `,
},
{
Name: "Name" ,
Type: reflect.TypeOf( "abc" ),
Tag: `json: "name" `,
},
})
fmt.Println(tt.FieldByIndex([] int {0}))
}
|
Output:
{Height float64 json:"height" 0 [0] false}
Example 2:
package main
import (
"fmt"
"reflect"
)
type User struct {
Id int
Name string
Age int
}
type Manager struct {
User
Title string
}
func main() {
m := Manager{User: User{1, "Jack" , 12}, Title: "123" }
t := reflect.TypeOf(m)
fmt.Printf( "%#v\n" , t.Field(0))
fmt.Printf( "%#v \n" , t.Field(1))
fmt.Printf( "%#v \n" , t.FieldByIndex([] int {0, 0}))
fmt.Printf( "%#v \n" , t.FieldByIndex([] int {0, 1}))
fmt.Printf( "%#v \n" , t.FieldByIndex([] int {0, 2}))
}
|
Output:
reflect.StructField{Name:”User”, PkgPath:””, Type:(*reflect.rtype)(0x4b1480), Tag:””, Offset:0x0, Index:[]int{0}, Anonymous:true}
reflect.StructField{Name:”Title”, PkgPath:””, Type:(*reflect.rtype)(0x4a1c20), Tag:””, Offset:0x20, Index:[]int{1}, Anonymous:false}
reflect.StructField{Name:”Id”, PkgPath:””, Type:(*reflect.rtype)(0x4a14e0), Tag:””, Offset:0x0, Index:[]int{0}, Anonymous:false}
reflect.StructField{Name:”Name”, PkgPath:””, Type:(*reflect.rtype)(0x4a1c20), Tag:””, Offset:0x8, Index:[]int{1}, Anonymous:false}
reflect.StructField{Name:”Age”, PkgPath:””, Type:(*reflect.rtype)(0x4a14e0), Tag:””, Offset:0x18, Index:[]int{2}, Anonymous:false}
Last Updated :
03 May, 2020
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