Python Question: Year and Day of Year to date?

datetime.datetime(year, 1, 1) + datetime.timedelta(days - 1)

>>> import datetime
>>> datetime.datetime.strptime('2010 120', '%Y %j')
datetime.datetime(2010, 4, 30, 0, 0)
>>> _.strftime('%d/%m/%Y')
'30/04/2010'

The toordinal() and fromordinal() functions of the date class could be used:

from datetime import date
date.fromordinal(date(year, 1, 1).toordinal() + days - 1)