Golang：如何从字符串中替换第n个字符

Question

I want to replace nth char from in the original string, I can access nth char from string by using chars[i], but when I assign value to chars[i] it giving error.

package main
import "fmt"

func main() {
  var chars = "abcdef"
  fmt.Println(string(chars[3]))
  chars[3] = "z" // is not working, 
}

Answer 1

This is happening because chars is actually a string and is immutable. If you declared it appropriately (as a byte slice) then you can assign to it as you're attempting. Here's an example;

package main
import "fmt"

func main() {
  var chars = []byte{'a', 'b', 'c', 'd', 'e', 'f'}
  fmt.Println(string(chars[3]))
  fmt.Printf("%T
", chars)
  chars[3] = 'z'
  fmt.Println(string(chars))
}

https://play.golang.org/p/N1sSsfIBQY

Alternately you could use reslicing as demonstrated in the other answer.