python如何将日期时间日期转换为十进制年份 [英] python how to convert datetime dates to decimal years

问题描述

我正在寻找一种将datetime对象转换为十进制年的方法。以下是一个例子

I am looking for a way to convert datetime objects to decimal year. Below is an example

>>> obj = SomeObjet()
>>> obj.DATE_OBS
datetime.datetime(2007, 4, 14, 11, 42, 50)

如何将datetime.datetime（2007,4,14，11，42，50）转换为十进制数？从这种格式dd / mm / yyyy到这种格式yyyy.yyyy

How do i convert datetime.datetime(2007, 4, 14, 11, 42, 50) to decimal years? From this format dd/mm/yyyy to this kind of format yyyy.yyyy

推荐答案

from datetime import datetime as dt
import time

def toYearFraction(date):
    def sinceEpoch(date): # returns seconds since epoch
        return time.mktime(date.timetuple())
    s = sinceEpoch

    year = date.year
    startOfThisYear = dt(year=year, month=1, day=1)
    startOfNextYear = dt(year=year+1, month=1, day=1)

    yearElapsed = s(date) - s(startOfThisYear)
    yearDuration = s(startOfNextYear) - s(startOfThisYear)
    fraction = yearElapsed/yearDuration

    return date.year + fraction

演示：

>>> toYearFraction(dt.today())
2011.47447514

此方法可能是准确的第二（或者如果夏令时或其他奇怪的地区事情有效）。它也可以在leapyears期间正常工作。如果您需要大量的解决方案（例如由于地球旋转的变化），您最好查询网络服务。

This method is probably accurate to within the second (or the hour if daylight savings or other strange regional things are in effect). It also works correctly during leapyears. If you need drastic resolution (such as due to changes in the Earth's rotation) you are better off querying a net service.

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