reflect.Copy() 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.Copy() Function in Golang is used to copies the contents of the source into destination until either destination has been filled or source has been exhausted. To access this function, one needs to imports the reflect package in the program.
Syntax:
func Copy(dst, src Value) int
Parameters: This function takes two parameters of Slice or Array type. And dst and src must have the same element type.
Return Value: This function returns the number of elements copied.
Below examples illustrate the use of above method in Golang:
Example 1:
package main
import (
"fmt"
"reflect"
)
func main() {
src := reflect.ValueOf([] int {10, 20, 32})
dest := reflect.ValueOf([] int {1, 2, 3})
cnt := reflect.Copy(dest, src)
data := dest.Interface().([] int )
data[0] = 100
fmt.Println( "Number of element Copied :" , cnt)
fmt.Println( "Source :" , src)
fmt.Println( "destination :" , dest)
}
|
Output:
Number of element Copied : 3
Source : [10 20 32]
destination : [100 20 32]
Example 2:
package main
import (
"fmt"
"reflect"
)
type temp struct {
A0 [] int
A1 [] int
}
func main() {
var val temp
val.A0 = append(val.A0, [] int {1, 2, 3,
4, 5, 6, 7, 8, 9}...)
val.A1 = append(val.A1, 9, 8, 7, 6)
var n = reflect.Copy(reflect.ValueOf(val.A0),
reflect.ValueOf(val.A1))
fmt.Println( "Number of element Copied :" , n)
fmt.Println( "{Source, destination} :" , val)
}
|
Output:
Number of element Copied : 4
{Source, destination} : {[9 8 7 6 5 6 7 8 9] [9 8 7 6]}
Last Updated :
28 Apr, 2020
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