We can do this sort of thing with the advent of the format
method since python2.6:
>>> import datetime
>>> '{dt.year}/{dt.month}/{dt.day}'.format(dt = datetime.datetime.now())
'2013/4/19'
Though perhaps beyond the scope of the original question, for more interesting formats, you can do stuff like:
>>> '{dt:%A} {dt:%B} {dt.day}, {dt.year}'.format(dt=datetime.datetime.now())
'Wednesday December 3, 2014'
And as of python3.6, this can be expressed as an inline formatted string:
Python 3.6.0a2 (v3.6.0a2:378893423552, Jun 13 2016, 14:44:21)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import datetime
>>> dt = datetime.datetime.now()
>>> f'{dt:%A} {dt:%B} {dt.day}, {dt.year}'
'Monday August 29, 2016'