将Weekday字符串解析为时间. [英] Parse Weekday string into time.Weekday

问题描述

我遇到了将星期几"字符串转换为time.Weekday值的问题.我找不到time包中内置的任何内容.

I've came across a problem to convert a Day of Week string into a time.Weekday value. I couldn't find anything built into the time package.

然后，我编写了这个简单的函数(满足了我的需求):

Then I've written this simple function (that covers my needs):

var daysOfWeek = [...]string{
    "Sunday",
    "Monday",
    "Tuesday",
    "Wednesday",
    "Thursday",
    "Friday",
    "Saturday",
}

func parseWeekday(v string) (time.Weekday, error) {
    for i := range daysOfWeek {
        if daysOfWeek[i] == v {
            return time.Weekday(i), nil
        }
    }

    return time.Sunday, fmt.Errorf("invalid weekday '%s'", v)
}

还有其他推荐或更多惯用方式在Golang中执行此转换吗?

Is there any other recommended or more idiomatic way to perform this conversion in Golang?

谢谢！

推荐答案

前言:我在 timex.ParseWeekday() .

是的，使用映射而不是数组，因此查找更快，更直接:

Yes, use a map instead of an array, so lookups are faster and more straight-forward:

var daysOfWeek = map[string]time.Weekday{
    "Sunday":    time.Sunday,
    "Monday":    time.Monday,
    "Tuesday":   time.Tuesday,
    "Wednesday": time.Wednesday,
    "Thursday":  time.Thursday,
    "Friday":    time.Friday,
    "Saturday":  time.Saturday,
}

func parseWeekday(v string) (time.Weekday, error) {
    if d, ok := daysOfWeek[v]; ok {
        return d, nil
    }

    return time.Sunday, fmt.Errorf("invalid weekday '%s'", v)
}

测试:

fmt.Println(parseWeekday("Monday"))
fmt.Println(parseWeekday("Friday"))
fmt.Println(parseWeekday("invalid"))

输出(在转到Playgorund 上尝试):

Monday <nil>
Friday <nil>
Sunday invalid weekday 'invalid'

提示:

您甚至可以使用for循环来安全地初始化daysOfWeek映射，如下所示:

You can even use a for loop to initialize safely the daysOfWeek map like this:

var daysOfWeek = map[string]time.Weekday{}

func init() {
    for d := time.Sunday; d <= time.Saturday; d++ {
        daysOfWeek[d.String()] = d
    }
}

测试和输出是相同的.在游乐场上尝试一下.

Testing and output is the same. Try this one on the Go Playground.

此映射解决方案的另一个不错的属性(与数组解决方案相比)是，您可以在同一映射中列出可以解析为time.Weekday的其他有效值，而无需其他解析代码.

Another nice property of this map-solution (compared to your array-solution) is that you may list additional valid values in the same map that may be parsed into time.Weekday without additional parsing code.

例如，让我们还将3个字母的简短工作日名称解析为与它们对应的time.Weekday，例如"Mon"到time.Monday.

For example, let's also parse the 3-letter short weekday names into their time.Weekday equivalent, e.g. "Mon" to time.Monday.

可以通过一个简单的循环添加此扩展名:

This extension can be added with a simple loop:

var daysOfWeek = map[string]time.Weekday{}

func init() {
    for d := time.Sunday; d <= time.Saturday; d++ {
        name := d.String()
        daysOfWeek[name] = d
        daysOfWeek[name[:3]] = d
    }
}

测试:

fmt.Println(parseWeekday("Monday"))
fmt.Println(parseWeekday("Friday"))
fmt.Println(parseWeekday("Mon"))
fmt.Println(parseWeekday("Fri"))
fmt.Println(parseWeekday("invalid"))

输出(在游乐场上尝试):

Monday <nil>
Friday <nil>
Monday <nil>
Friday <nil>
Sunday invalid weekday 'invalid'

看到类似的问题:从字符串中获取整数月份值

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