python - Python 中的日期计算

Question

我对 Python 比较陌生，我正在尝试编写以下日期计算函数

• 查找指定日期时间是/曾经是星期一的日期
• 在指定的日期时间找到该月的第一个非周末
• 查找指定日期时间中一年中的第一个非周末
• 在指定日期时间找到一个月的第 N [星期几]

到目前为止，这是我的尝试 - 如果可以改进(或更正)逻辑以使其更“Pythonic”，请告诉我

import datetime

def find_month_first_monday(tstamp = datetime.today()):
    day_of_month = datetime.date.today().timetuple()[2]
    day_of_week = datetime.weekday(tstamp)
    # now I have the dow, and dom, I can index into a 2D array of
    # dates for the month - IF I knew how to get to that array ...


def find_first_gbd_in_month(tstamp = datetime.today()):
    # naive way would be to find the month and year from the passed in arg,
    # calculate the first day for that month/year and iterate until a non-weekend day
    # is found. Not elegant, there must be a better way
    pass


def find_first_gbd_in_year(tstamp = datetime.today()):
   # Ditto, as above.
    pass


def find_ndow_in_month(tstamp = datetime.today()):
    # again, I can get the month and the year from the passed in argument
    # what I need is a 2D array of dates for the month/year, so I can get
    # the nth dow (similar to reading off a calendar)
    pass

Answer 1

find_month_first_monday

我会使用不同的算法。首先，找到该月的第一天。

first_day_of_month = datetime.date.today().replace(day=1)

并找到 first_day_of_month 的星期几，

week_day = first_day_of_month.weekday()

并在必要时添加天数。

if week_day:
  first_day_of_month += datetime.timedelta(days=7-week_day)

find_first_gbd_in_month

类似于 find_month_first_monday，但仅当 week_day 为 5 或 6(周六和周日)时才添加日期。

find_first_gbd_in_year

同时在 .replace 中提供 month=1 参数。

find_ndow_in_month

找到一周的第一天，然后添加 n-1 周。