simpe-normalization.go

package main

import (
    "fmt"
    "strings"
    )

func main() {
    data := "São Paulo, Brazil. Wien, Österreich."
    fmt.Printf("Before: %s\n", data)
    
    after := strings.Map(normalize, data)
    fmt.Printf("After: %s\n", after)
}

func normalize(in rune) rune {
    switch in {
    case 'ã':
        return 'a'
    case 'Ö':
        return 'O'
    }
    return in
}