String, rune slice

In Go we often use strings to store character data. But rune slices have many advantages—they treat characters in a more consistent way.

For Unicode characters, a rune slice can be used to append and modify characters with no errors. If we act on a string directly, we can cause problems here.

Modify runes example

A string contains runes (these are characters). We can convert a string to a slice of runes. Then we can modify runes or add new ones.

package main

import "fmt"

func main() {
    original := "cat"
    fmt.Println(original)

    // Get rune slice.
    // ... Modify the slice's data.
    r := []rune(original)
    r[0] = 'm';
    r = append(r, 'e')

    // Create new string from modified slice.
    result := string(r)
    fmt.Println(result)
}
cat
mate

Substrings, notes

Rune slices are also ideal for acquiring substrings from a string. This supports Unicode characters with no risk of data corruption.

Converting a string to a rune slice in Go is a common operation. It leads to code that will be less likely to corrupt Unicode characters.