英文:
What is the "idiomatic" version of this function?
问题
尝试理解Go语言的思维方式。我编写了以下函数，用于查找文件夹中具有日期的*.txt文件，获取最新的日期并返回该日期。
func getLatestDate(path string) (time.Time, error) {
if fns, e := filepath.Glob(filepath.Join(path, "*.txt")); e == nil {
re, _ := regexp.Compile(`_([0-9]{8}).txt$`)
max := ""
for _, fn := range fns {
if ms := re.FindStringSubmatch(fn); ms != nil {
if ms[1] > max {
max = ms[1]
}
}
}
date, _ := time.Parse("20060102", max)
return date, nil
} else {
return time.Time{}, e
}
}
如果有更符合Go语言习惯的版本，它会是什么样子呢？
英文:
Trying to understand the mentality of Go. I wrote the following function which looks for *.txt files of a folder that have a date in the filename, get the latest date and return that date.
func getLatestDate(path string) (time.Time, error) {
if fns, e := filepath.Glob(filepath.Join(path, "*.txt")); e == nil {
re, _ := regexp.Compile(`_([0-9]{8}).txt$`)
max := ""
for _, fn := range fns {
if ms := re.FindStringSubmatch(fn); ms != nil {
if ms[1] > max {
max = ms[1]
}
}
}
date, _ := time.Parse("20060102", max)
return date, nil
} else {
return time.Time{}, e
}
}
What would be the more idiomatic version of this function, if there is one?
答案1
得分: 11
这是我的建议：
- 使用
MustCompile编译静态正则表达式。如果无法编译，它会引发错误并保存错误检查。 - 将编译正则表达式的过程提升到函数外部 - 只需要编译一次。请注意，我将其以小写字母开头，这样在包外部将不可见。
- 在检查错误时使用早期返回 - 这样可以减少缩进，并符合Go的惯用法。
- 对于这些早期返回，使用命名返回参数 - 这样可以避免为类型定义nil值和进行类型输入（尽管不是每个人都喜欢这样做）。
- 直接返回
time.Parse，它会检查错误（之前你没有这样做）。
代码示例：
var dateRe = regexp.MustCompile(`_([0-9]{8}).txt$`)
func getLatestDate(path string) (date time.Time, err error) {
fns, err := filepath.Glob(filepath.Join(path, "*.txt"))
if err != nil {
return
}
max := ""
for _, fn := range fns {
if ms := dateRe.FindStringSubmatch(fn); ms != nil {
if ms[1] > max {
max = ms[1]
}
}
}
return time.Parse("20060102", max)
}
英文:
Here is my take
- Use
MustCompileto compile a static regexp. This will panic if it doesn't compile and saves an error check - Hoist compiling the regexp out of the function - you only need it compiled once. Note that I've called it with a lowercase initial letter so it won't be visible outside the package.
- Use an early return when checking errors - this saves indentation and is idiomatic go
- Use named return parameters for those early returns - saves defining nil values for types and typing in general (not to everyone's taste though)
return time.Parsedirectly which checks the errors (you weren't before)
The code
var dateRe = regexp.MustCompile(`_([0-9]{8}).txt$`)
func getLatestDate(path string) (date time.Time, err error) {
fns, err := filepath.Glob(filepath.Join(path, "*.txt"))
if err != nil {
return
}
max := ""
for _, fn := range fns {
if ms := dateRe.FindStringSubmatch(fn); ms != nil {
if ms[1] > max {
max = ms[1]
}
}
}
return time.Parse("20060102", max)
}
答案2
得分: 0
这是我会如何编写它。不要忽略错误，使用守卫子句进行错误处理，并且不要在循环内重新编译正则表达式。
var datePat = regexp.MustCompile(`_([0-9]{8}).txt$`)
func getLatestDate(path string) (time.Time, error) {
fns, err := filepath.Glob(filepath.Join(path, "*.txt"))
if err != nil {
return time.Time{}, err
}
max := time.Time{}
for _, fn := range fns {
if ms := re.FindStringSubmatch(fn); ms != nil {
if t, err := time.Parse("20060102", ms[1]); err == nil && t.After(max) {
max = t
}
}
}
return max, nil
}
英文:
Here's how I would have written it. Don't ignore errors, use guard clauses for error handling, and don't recompile regexps inside a loop.
var datePat = regexp.MustCompile(`_([0-9]{8}).txt$`)
func getLatestDate(path string) (time.Time, error) {
fns, err := filepath.Glob(filepath.Join(path, "*.txt"))
if err != nil {
return time.Time{}, err
}
max := time.Time{}
for _, fn := range fns {
if ms := re.FindStringSubmatch(fn); ms != nil {
if t, err := time.Parse("20060102", ms[1]); err == nil && t.After(max) {
max = t
}
}
}
return max, nil
}
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论