如何在Go中获得给定月份的第一个星期一？

Question

I'm trying to get the first Monday of a given month.

Best way I can come up with is to loop through first seven days and return when .Weekday() == "Monday". Is there a better way to do this?

Answer 1

By looking at the .Weekday() of the time, you can compute the first Monday.

package main

import (
    "fmt"
    "time"
)

// FirstMonday returns the day of the first Monday in the given month.
func FirstMonday(year int, month time.Month) int {
    t := time.Date(year, month, 1, 0, 0, 0, 0, time.UTC)
    return (8-int(t.Weekday()))%7 + 1
}

func main() {
    for m := 1; m <= 12; m++ {
        fmt.Println(m, FirstMonday(2013, time.Month(m)))
    }
}