计算两个日期之间的年差，余数以天表示，在 Python

Question

如果输出应该以年表示，余数以天表示，如何找到两个日期之间的差异？

示例 1：如果两个日期是 June 1, 1981 和 August 23, 2001, 那么结果应该是 20 years and 83 days.

示例 2：如果两个日期是 January 1, 2002 和 December 30, 2003, 那么结果应该是 1 year and 363 days.

我不关心结果的格式；我只需要知道计算年数和天数的最 Pythonic 方法。

谢谢！

Answer 1

您需要使用 datetime 和 relativedelta 模块。

import datetime
from dateutil.relativedelta import relativedelta

start_date = datetime.datetime(1981,6,1)
end_date = datetime.datetime(2002,1,1)

difference_in_years = relativedelta(end_date, start_date)
print(difference_in_years)

Answer 2

使用内置模块datetime，您可以轻松获取天数。

>>> import datetime

>>> foo = datetime.date(2001, 8, 23) - datetime.date(1981, 6, 1)
>>> foo
datetime.timedelta(days=7388)
>>> foo.days
7388

>>> bar = datetime.date(2003, 12, 30) - datetime.date(2002, 1, 1)
>>> bar
datetime.timedelta(days=728)
>>> bar.days
728

dateutil模块可以给你年数，但是月数也丢进去了

>>> import datetime
>>> from dateutil.relativedelta import relativedelta

>>> relativedelta(datetime.date(2001, 8, 23), datetime.date(1981, 6, 1))
relativedelta(years=+20, months=+2, days=+22)

>>> relativedelta(datetime.date(2003, 12, 30), datetime.date(2002, 1, 1))
relativedelta(years=+1, months=+11, days=+29)

不过，在使用月数时要小心。一个月和一天没有定义。上一示例中的 11 个月是 6 个 31 天的月份、4 个 30 天的月份和 1 个 28 天的月份的组合。所以，一般来说，你不能用它来获取天数。我建议写一个函数来获得你想要的形式的差异。

import calendar
import datetime
from dateutil.relativedelta import relativedelta

def get_delta(date2, date1):
    '''calculate the delta between two datetime.date objects (date2 the newer date)'''

    number_of_leap_years = sum(1
                               for yr in range(date1.year, date2.year + 1)
                               if calendar.isleap(yr))
    number_of_years = relativedelta(date2, date1).years

    total_number_of_days = (date2 - date1).days
    number_of_days = total_number_of_days
                     - 365 * number_of_years
                     - number_of_leap_years

    return f'{number_of_years} years, {number_of_days} days'

计算两个日期之间的年差，余数以天表示，在 Python

Find difference between two dates in years, with the remainder expressed in days, in Python

python

output

date-arithmetic