strings.Mapstrings.Map
func Map(mapping func(rune) rune, s string) string
mappingrunes
strings.Map
package main

import (
    "fmt"
    "strings"
)

func main() {
    str := "hello, world!"
    result := strings.Map(func(r rune) rune {
        return rune(int(r) - 32)
    }, str)
    fmt.Println(result)
}
Map-32
HELLO, WORLD!
strings.Map