How Do I Convert Weekday Strings to time.Weekday in Go Efficiently?

Parse Weekday String into time.Weekday: An Idiomatic Approach with a Map

Converting a weekday string into a corresponding time.Weekday value in Go requires a custom solution since there's no built-in functionality for this conversion. While the presented array-based function provides a workable solution, a map-based approach offers advantages in efficiency and flexibility.

Enhanced Solution Using a Map

Instead of using an array, utilizing a map with weekday strings as keys and their corresponding time.Weekday values as values significantly speeds up lookups and simplifies the code:

<code class="go">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)
}</code>

Benefits of the Map-Based Approach

• Faster lookups: Maps provide O(1) lookup time, making them more efficient than iterating through an array.
• Straightforward initialization: Initializing a map is easier, especially when done with a for loop, as shown in this example:

<code class="go">var daysOfWeek = map[string]time.Weekday{}

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

Expanding the Map for Additional Input

This map-based approach also allows for the flexible addition of new valid values that can be parsed into time.Weekday. For example, short 3-letter weekday names can be included with a simple loop:

<code class="go">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
    }
}</code>

This extension allows parsing both full weekday names (e.g., "Monday") and short weekday names (e.g., "Mon") into time.Weekday.

Using a map in this context provides a faster, more convenient, and extendable way to parse weekday strings into time.Weekday values in Go.

The above is the detailed content of How Do I Convert Weekday Strings to time.Weekday in Go Efficiently?. For more information, please follow other related articles on the PHP Chinese website!