How to Convert String to Bytes in Go

Using byte Function

The easiest way to convert string to []byte in Golang:

package main

import "fmt"

func main() {
  s := "Hello"

  b := []byte(s)
  fmt.Printf("%v\n", b)
}

[72 101 108 108 111]

Using copy Function

The copy built-in function copies elements from a source slice into a destination slice.

You can use copy function to assign string to bytes. The following example:

package main

import "fmt"

func main() {
  s := "Hello"

  b := [3]byte{}
  copy(b[:], s)
  fmt.Printf("%v\n", b)

  c := [7]byte{}
  copy(c[:], s)
  fmt.Printf("%v\n", c)
}

[72 101 108]
[72 101 108 108 111 0 0]

If the string is too long, copy will only copy the part of the string that fits (and multi-byte runes may then be copied only partly, which will corrupt the last rune of the resulting string).