Convert Year/Month/Day to Day of Year in Python
I'm using the datetime
module, i.e.:
>>> import datetime
>>> today = datetime.datetime.now()
>>> print(today)
2009-03-06 13:24:58.857946
and I would like to compute the day of year that takes leap years into account. e.g. today (March 6, 2009) is the 65th day of 2009.
I see a two options:
-
Create a
number_of_days_in_month = [31, 28, ...]
array, decide if it's a leap year and manually sum up the days. -
Use
datetime.timedelta
to make a guess & then binary search for the correct day of the year:>>> import datetime >>> YEAR = 2009 >>> DAY_OF_YEAR = 62 >>> d = datetime.date(YEAR, 1, 1) + datetime.timedelta(DAY_OF_YEAR - 1)
These both feel pretty clunky & I have a gut feeling that there's a more "Pythonic" way of calculating the day of the year. Any ideas/suggestions?
Solution 1:
Use datetime.timetuple()
to convert your datetime
object to a time.struct_time
object then get its tm_yday
property:
from datetime import datetime
day_of_year = datetime.now().timetuple().tm_yday # returns 1 for January 1st
Solution 2:
You could use strftime
with a %j
format string:
>>> import datetime
>>> today = datetime.datetime.now()
>>> today.strftime('%j')
'065'
but if you wish to do comparisons or calculations with this number, you would have to convert it to int()
because strftime()
returns a string. If that is the case, you are better off using DzinX's answer.