python 计算两个日期相差多少个月

近期，因为业务须要计算两个日期以前相差多少个月。我在网上找了好久，结果发现万能的python，竟然没有一个模块计算两个日期的月数，像Java、C#之类的高级语言，都会有(date1-date2).months的现成方法，以为难以想象。说句实在的，一直以为python 的日期处理模块真心很差用。

　　哦，对了，别跟我说 datetime, calendar, dateutil 这些模块，由于我都试过了，都没用。有个居然算出来还有错。datetime.timedelta只能计算出日时分秒。对年月却不支持。网上一搜，一大堆的。

　　dateutil.rrule这个例子是我好不容易找到的，请看个人测试结果：

import datetime

from dateutil import rrule

d1 = datetime.date(2016, 2, 29)
d2 = datetime.date(2019, 3, 31)

months = rrule.rrule(rrule.MONTHLY, dtstart=d1, until=d2).count()

print(f"months={months}")

　　看到这样的结果，我只能呵呵了。

　　废话很少少，献上本身写的代码：

　　该代码返回，（月,小数月）

import datetime
import calendar as c


d1 = datetime.date(2016, 2, 29)
d2 = datetime.date(2019, 3, 31)


def calmonths(startdate, enddate):
# 计算两个日期相隔月差
samemonthdate = None
try:
samemonthdate = datetime.date(enddate.year, enddate.month,
startdate.day)
except Exception as e:
print(e)
samemonthdate = datetime.date(enddate.year, enddate.month,
c.monthrange(enddate.year,
enddate.month)[1])


    holdmonths = 0
    decimalmonth = 0.0
    if samemonthdate > enddate:
        premanthdate = None
        try:
            premanthdate = datetime.date(enddate.year, enddate.month - 1,
                                             startdate.day)
        except Exception as e:
            print(e)
            premanthdate = datetime.date(enddate.year, enddate.month - 1,
                                             c.monthrange(
                                                 enddate.year,
                                                 enddate.month - 1)[1])
        currmonthdays = (samemonthdate - premanthdate).days
        holdmonths = (premanthdate.year - startdate.year
                      ) * 12 + premanthdate.month - startdate.month
        decimalmonth = (enddate - premanthdate).days / currmonthdays




    elif samemonthdate < enddate:
        nextmonthdate = None
        try:
            nextmonthdate = datetime.date(enddate.year, enddate.month + 1,
                                              startdate.day)
        except Exception as e:
            nextmonthdate = datetime.date(enddate.year, enddate.month + 1,
                                              c.monthrange(
                                                  enddate.year,
                                                  enddate.month + 1)[1])
        currmonthdays = (nextmonthdate - samemonthdate).days
        holdmonths = (samemonthdate.year - startdate.year
                      ) * 12 + samemonthdate.month - startdate.month
        decimalmonth = (enddate - samemonthdate).days / currmonthdays




    else:
        holdmonths = (enddate.year - startdate.year
                      ) * 12 + enddate.month - startdate.month




    return holdmonths, decimalmonth




months = calmonths(d1, d2)




print(f"months={months}")

欢迎各类暴力测试，有问题留言反馈。