How to replace nth char from a string in Go

问题

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

package main
import "fmt"

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

回答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\n", 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.

回答2:

Strings are immutable.

chars = chars[:3] + "z" + chars[4:]

回答3:

Use slice indexing to remove the character at the index, and place a new character there instead.

package main
import "fmt"

func main() {
  var chars = "abcdef"
  fmt.Println(string(chars[3]))
  chars = chars[:3] + "z" + chars[3+1:]
  fmt.Println(string(chars[3]))
}

Output:

d
z

[:3] selects everything in the slice from the beginning up until the index 3, and [3+1:] selects everything from the index (3+1) until the end of the slice. Put the character you wanted in-between the two statements and cat them all together for the effect of replacing a character at a specific index.

If you want to replace a specific character (i.e. all (or some of) the instances of the letter 'b') you can use the strings.Replace function.

来源：https://stackoverflow.com/questions/37688457/how-to-replace-nth-char-from-a-string-in-go

标签

string

replace