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reflect.Field() Function in Golang with Examples

  • Last Updated : 03 May, 2020

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.Field() Function in Golang is used to get the i’th field of the struct v. To access this function, one needs to imports the reflect package in the program.

Syntax:

func (v Value) Field(i int) Value

Parameters: This function does not accept any parameters.

Return Value: This function returns the i’th field of the struct v.

Below examples illustrate the use of the above method in Golang:



Example 1:




// Golang program to illustrate
// reflect.Field() Function 
   
package main
   
import (
    "fmt"
    "reflect"
)
   
// Main function
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.NumField()) 
  
    //use of Field() method
    fmt.Println(tt.Field(0))
    fmt.Println(tt.Field(1))
   
}    

Output:

2
{Height  float64 json:"height" 0 [0] false}
{Name  string json:"name" 8 [1] false}

Example 2:




// Golang program to illustrate
// reflect.Field() Function 
     
package main
     
import (
    "fmt"
    "reflect"
)
   
type temp struct {  
    ord      int
    cId int
}
   
// function to use the 
// Field() method 
func useKind(val interface{}) {  
   
    // Kind() function is used
    // to find the kind
    if reflect.ValueOf(val ).Kind() == reflect.Struct {
        v := reflect.ValueOf(val )
        fmt.Println("Number of fields", v.NumField())
        for i := 0; i < v.NumField(); i++ {
            fmt.Printf("Field: %d \t type: %T \t value: %v\n",
                                    i, v.Field(i), v.Field(i))
        }
    }
   
   
}
    
// Main function 
func main() {  
    val := temp {
        ord: 1,
        cId: 513,
    }
    useKind(val)
   
}   

Output:

Number of fields 2
Field: 0      type: reflect.Value      value: 1
Field: 1      type: reflect.Value      value: 513



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