How to go from []bytes to get hexadecimal

Question

If I understood correctly you want to return the %x format:

you can import "encoding/hex" and use the EncodeToString method

str := hex.EncodeToString(h.Sum(nil))

or just Sprintf the value:

func md(str string) string {
    h := md5.New()
    io.WriteString(h, str)
    
    return fmt.Sprintf("%x", h.Sum(nil))
}

note that Sprintf is slower because it needs to parse the format string and then reflect based on the type found

http://play.golang.org/p/vsFariAvKo