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)
} |
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" ))
} |
Output:
Value_1 : Geeks_1
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