What methods can be used to replace a specific character or substring within a string?

In Go, to replace characters or substrings within a string, the functions from the strings package are typically used:

• strings.Replace — replaces a specified number of occurrences of a substring with another substring.
• strings.ReplaceAll — replaces all occurrences of a substring with another.

Example of replacing a character:

import (
    "fmt"
    "strings"
)

func main() {
    s := "hello world"
    // Replace all 'l' with 'x'
    newStr := strings.ReplaceAll(s, "l", "x")
    fmt.Println(newStr) // hexxo worxd
}

To replace a character by index, strings in Go are immutable, so you can convert the string to a rune slice, modify the needed element, and convert back:

s := "hello"
runes := []rune(s)
runes[1] = 'a' // replace 'e'
 s = string(runes) // hallo

Thus, for substring replacement, use strings.Replace or strings.ReplaceAll, and for character replacement by position, convert to rune slice.