我使用replace()方法并编写了这个递归函数。dt是一个日期时间。datetime对象:

def month_timedelta(dt, m):
    y = m // 12
    dm = m % 12
    if y == 0:
        if dt.month + m <= 12:
            return dt.replace(month = dt.month + m)
        else:
            dy = (dt.month + m) // 12
            ndt = dt.replace(year=dt.year + dy)
            return ndt.replace(month=(ndt.month + m) % 12)
    else:
        return month_timedelta(dt.replace(year=dt.year + y),dm)

假设你的datetime变量叫做date:

date=datetime.datetime(year=date.year+int((date.month+6)/12),
                       month=(date.month+6)%13 + (1 if (date.month + 
                       months>12) else 0), day=date.day)

按月开始计算:

from datetime import timedelta
from dateutil.relativedelta import relativedelta

end_date = start_date + relativedelta(months=delta_period) + timedelta(days=-delta_period)

import time

def add_month(start_time, months):  

        ret = time.strptime(start_time, '%Y-%m-%d')
        t = list(ret)

        t[1] += months

        if t[1] > 12:
            t[0] += 1 + int(months / 12)

            t[1] %= 12

        return int(time.mktime(tuple(t)))

使用Python标准库，即没有dateutil或其他，并解决“2月31日”问题:

import datetime
import calendar

def add_months(date, months):
    months_count = date.month + months

    # Calculate the year
    year = date.year + int(months_count / 12)

    # Calculate the month
    month = (months_count % 12)
    if month == 0:
        month = 12

    # Calculate the day
    day = date.day
    last_day_of_month = calendar.monthrange(year, month)[1]
    if day > last_day_of_month:
        day = last_day_of_month

    new_date = datetime.date(year, month, day)
    return new_date

测试:

>>>date = datetime.date(2018, 11, 30)

>>>print(date, add_months(date, 3))
(datetime.date(2018, 11, 30), datetime.date(2019, 2, 28))

>>>print(date, add_months(date, 14))
(datetime.date(2018, 12, 31), datetime.date(2020, 2, 29))

我找不到这个问题的确切解决方案，所以我将发布我的解决方案，以防使用标准日历和datetime库可能有任何帮助。这适用于添加和减去月份，并考虑月末滚动和最后一个月比第一个月天数少的情况。如果你正在寻找更复杂的操作，我还有一个更通用的解决方案，它添加了定期间隔(天，月，年，季度，学期等)，如:“1m”，“-9m”，“-1.5y”，“-3q”，“1s”等。

from datetime import datetime
from calendar import monthrange
def date_bump_months(start_date, months):
    """
    bumps months back and forth. 
    --> if initial date is end-of-month, i will move to corresponding month-end
    --> ir inital date.day is greater than end of month of final date, it casts it to momth-end
    """
    signbit = -1 if months < 0 else 1
    d_year, d_month = divmod(abs(months),12)    
    end_year = start_date.year + d_year*signbit 
    end_month = 0
    if signbit ==-1:            
        if d_month < start_date.month:
            end_month = start_date.month - d_month
        else:
            end_year -=1
            end_month = 12 - (d_month - start_date.month)
    else:
        end_month +=start_date.month
        if end_month  > 12:
            end_year +=1
            end_month -=12
    # check if we are running end-of-month dates
    eom_run = monthrange(start_date.year, start_date.month)[1]==start_date.day
    eom_month = monthrange((end_year), (end_month))[1]
    if eom_run:
        end_day = eom_month 
    else:
        end_day = min(start_date.day, eom_month )    
    return date(end_year, end_month, end_day)