How to convert Python datetime dates to decimal/float years

Question

I am looking for a way to convert datetime objects to decimal(/float) year, including fractional part. Example:

>>> obj = SomeObjet()
>>> o         


        

Answer 1

I'm assuming that you are using this to compare datetime values. To do that, please use the the timedelta objects instead of reiniventing the wheel.

Example:

>>> from datetime import timedelta
>>> from datetime import datetime as dt
>>> d = dt.now()
>>> year = timedelta(days=365)
>>> tomorrow = d + timedelta(days=1)
>>> tomorrow + year > d + year
True

If for some reason you truly need decimal years, datetime objects method strftime() can give you an integer representation of day of the year if asked for %j - if this is what you are looking for, see below for a simple sample (only on 1 day resolution):

>>> from datetime import datetime
>>> d = datetime(2007, 4, 14, 11, 42, 50)
>>> (float(d.strftime("%j"))-1) / 366 + float(d.strftime("%Y"))
2007.2814207650274