python 計算兩個日期相差多少個月

近期，因爲業務須要計算兩個日期以前相差多少個月。我在網上找了好久，結果發現萬能的python，竟然沒有一個模塊計算兩個日期的月數，像Java、C#之類的高級語言，都會有(date1-date2).months的現成方法，以爲難以想象。說句實在的，一直以爲python 的日期處理模塊真心很差用。

　　哦，對了，別跟我說 datetime, calendar, dateutil 這些模塊，由於我都試過了，都沒用。有個居然算出來還有錯。datetime.timedelta只能計算出日時分秒。對年月卻不支持。網上一搜，一大堆的。

　　dateutil.rrule這個例子是我好不容易找到的，請看個人測試結果：

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}")

　　看到這樣的結果，我只能呵呵了。

　　廢話很少少，獻上本身寫的代碼：

　　該代碼返回，（月,小數月）

import datetime
import calendar as c


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


def calmonths(startdate, enddate):
# 計算兩個日期相隔月差
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}")

歡迎各類暴力測試，有問題留言反饋。