golang 截取字符串

//截取字符串 start 起点下标 end 终点下标(不包括)
func Substr(str string, start int, end int) string {
    rs := []rune(str)
    length := len(rs)

    if start < 0 || start > length {
        return ""
    }

    if end < 0 || end > length {
        return ""
    }
    return string(rs[start:end])
}