我正在使用datetime Python模块。我希望从当前日期计算6个月的日期。有人能帮我一下吗?

我想从当前日期生成一个6个月后的日期的原因是为了生成一个回顾日期。如果用户在系统中输入数据,系统将有从输入数据之日起6个月的审查日期。


当前回答

我们可能应该使用dateutil。relativedelta

然而,出于学术兴趣,我只想补充一点,在我发现它之前,我打算用这个:

亿: 今天代表。年度+ (K .今日month + 6) / 12 / (K . today . 12 month + 5%) + 1, K .今日day)。 except: 今天代表。年+ (K.today.month+6)//12 (K.today.month+6)%12+1, 1) -时间轴(天= 1)

它看起来很简单,但仍然可以捕捉到所有的问题,如29、30、31

它也适用于- 6 MTHS通过执行-timedelta

别被k弄糊涂了,今天它只是我程序中的一个变量

其他回答

我们可能应该使用dateutil。relativedelta

然而,出于学术兴趣,我只想补充一点,在我发现它之前,我打算用这个:

亿: 今天代表。年度+ (K .今日month + 6) / 12 / (K . today . 12 month + 5%) + 1, K .今日day)。 except: 今天代表。年+ (K.today.month+6)//12 (K.today.month+6)%12+1, 1) -时间轴(天= 1)

它看起来很简单,但仍然可以捕捉到所有的问题,如29、30、31

它也适用于- 6 MTHS通过执行-timedelta

别被k弄糊涂了,今天它只是我程序中的一个变量

我发现这个解决方法很好。(使用python-dateutil扩展名)

from datetime import date
from dateutil.relativedelta import relativedelta

six_months = date.today() + relativedelta(months=+6)

这种方法的优势在于,它可以处理28天、30天、31天的问题。这在处理业务规则和场景(比如发票生成等)时非常有用。

$ date(2010,12,31)+relativedelta(months=+1)
  datetime.date(2011, 1, 31)

$ date(2010,12,31)+relativedelta(months=+2)
  datetime.date(2011, 2, 28)
import datetime


'''
Created on 2011-03-09

@author: tonydiep
'''

def add_business_months(start_date, months_to_add):
    """
    Add months in the way business people think of months. 
    Jan 31, 2011 + 1 month = Feb 28, 2011 to business people
    Method: Add the number of months, roll back the date until it becomes a valid date
    """
    # determine year
    years_change = months_to_add / 12

    # determine if there is carryover from adding months
    if (start_date.month + (months_to_add % 12) > 12 ):
        years_change = years_change + 1

    new_year = start_date.year + years_change

    # determine month
    work = months_to_add % 12
    if 0 == work:
        new_month = start_date.month
    else:
        new_month = (start_date.month + (work % 12)) % 12

    if 0 == new_month:
        new_month = 12 

    # determine day of the month
    new_day = start_date.day
    if(new_day in [31, 30, 29, 28]):
        #user means end of the month
        new_day = 31


    new_date = None
    while (None == new_date and 27 < new_day):
        try:
            new_date = start_date.replace(year=new_year, month=new_month, day=new_day)
        except:
            new_day = new_day - 1   #wind down until we get to a valid date

    return new_date


if __name__ == '__main__':
    #tests
    dates = [datetime.date(2011, 1, 31),
             datetime.date(2011, 2, 28),
             datetime.date(2011, 3, 28),
             datetime.date(2011, 4, 28),
             datetime.date(2011, 5, 28),
             datetime.date(2011, 6, 28),
             datetime.date(2011, 7, 28),
             datetime.date(2011, 8, 28),
             datetime.date(2011, 9, 28),
             datetime.date(2011, 10, 28),
             datetime.date(2011, 11, 28),
             datetime.date(2011, 12, 28),
             ]
    months = range(1, 24)
    for start_date in dates:
        for m in months:
            end_date = add_business_months(start_date, m)
            print("%s\t%s\t%s" %(start_date, end_date, m))

我是这样解决这个问题的:

import calendar
from datetime import datetime
moths2add = 6
now = datetime.now()
current_year = now.year
current_month = now.month
#count days in months you want to add using calendar module
days = sum(
  [calendar.monthrange(current_year, elem)[1] for elem in range(current_month, current_month + moths)]
    )
print now + days

获得x个月之后或之前的下一个日期的一般函数。

from datetime import date

def after_month(given_date, month):
    yyyy = int(((given_date.year * 12 + given_date.month) + month)/12)
    mm = int(((given_date.year * 12 + given_date.month) + month)%12)

    if mm == 0:
        yyyy -= 1
        mm = 12
    return given_date.replace(year=yyyy, month=mm)


if __name__ == "__main__":
    today = date.today()
    print(today)

    for mm in [-12, -1, 0, 1, 2, 12, 20 ]:
        next_date = after_month(today, mm)
        print(next_date)