Copy function in Golang

How Copy function works ?

The built-in copy function copies the source element into the destination element and returns the destination element length.

  func Copy( dst , src [] Type) int

There are some special case using this function which is we can copy a string into an byte slice variable

  func Copy( dst []byte, src string) int

Examples:

package main
import "fmt"
func main() {
	var arr = make([]string, 2)
	n := copy(arr, []string{"hi", "hello", "welcome", "ll"})
	fmt.Println("element length :", n)
	fmt.Println("values :", arr)
}

Output:

element length : 2
values : [hi hello]

Special Case example:

package main
import "fmt"
func main() {
	var b = make([]byte, 5)
    // copy from a string to byte slice
	n := copy(b, "vicky")
	fmt.Println("element length :", n)
	fmt.Println("values :", string(b))
}

Output:

element length : 5
values : vicky