reflect.Set() 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.Set() Function in Golang is used to assigns x to the value v. To access this function, one needs to imports the reflect package in the program.
Syntax:
func (v Value) Set(x Value)Parameters: This function accept one parameter of Value type (x).
Return Value: This function does not returns any value.
Below examples illustrate the use of the above method in Golang:
Example 1:
// Golang program to illustrate // reflect.Set() Function package main import ( "fmt" "reflect" "unsafe" ) // Main function func main() { var s = struct { foo int }{654} var i int rs := reflect.ValueOf(&s).Elem() rf := rs.Field(0) ri := reflect.ValueOf(&i).Elem() rf = reflect.NewAt(rf.Type(), unsafe.Pointer(rf.UnsafeAddr())).Elem() ri.Set(rf) rf.Set(ri) fmt.Println(rf) fmt.Println(ri) } |
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Output:
654 654
Example 2:
// Golang program to illustrate // reflect.Set() Function package main import ( "fmt" "reflect" ) func sum(args []reflect.Value) []reflect.Value { a, b := args[0], args[1] if a.Kind() != b.Kind() { fmt.Println( "??? ????." ) return nil } switch a.Kind() { case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: return []reflect.Value{reflect.ValueOf(a.Int() + b.Int())} case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64: return []reflect.Value{reflect.ValueOf(a.Uint() + b.Uint())} case reflect.Float32, reflect.Float64: return []reflect.Value{reflect.ValueOf(a.Float() + b.Float())} case reflect.String: return []reflect.Value{reflect.ValueOf(a.String() + b.String())} default : return []reflect.Value{} } } func makeSum(fptr interface{}) { fn := reflect.ValueOf(fptr).Elem() v := reflect.MakeFunc(fn.Type(), sum) fn.Set(v) } // Main function func main() { var stringSum func(string, string) string makeSum(&stringSum) fmt.Println(stringSum( "Value_1 : " , "Geeks_1" )) } |
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Output:
Value_1 : Geeks_1