如何从字符串中获取有效的IETF语言标签

Question

I would like to convert locale tag to IETF standard. IETF language tag asserts en-US as a correct tag for American English. In may case, it's possible that I would get en_US as an input.

Currently I'm using this method:

func toLanguageTag(l string) string {
    return strings.Replace(l, "_", "-", -1)
}

For example, I know that Java has toLanguageTag method. Should I continue use this approach, or there is more preferable way to do what I want?

Answer 1

There's a package in the external packages repository of Go (maintained by the Go project but not part of the standard library), that handles parsing and validation of language tags.

https://godoc.org/golang.org/x/text/language

Example:

package main

import (
   "fmt"
   "golang.org/x/text/language"
)

func main() {
   tag := language.Make("en_us")
   fmt.Println(tag)
}
// Output: en-US

Note that language.Make() omits the error in case of an invalid tag. You should use language.Parse() which returns an error in practice.