# -*- coding: latin-1 -*-
"""
I am currently using the datetime package, but I find that the design is oddly
asymmetric. I would like to know why. Or perhaps I have misunderstood how it should be used?
I can make a datetime easily enough
>>> datetime(2005, 1, 1) datetime.datetime(2005, 1, 1, 0, 0)
What I find odd is that I cannot make a new datetime object from the timetuple()
like this:
>>> d1 = datetime(2005, 1, 1, 12, 13, 10)
>>> d2 = datetime(*d1.timetuple())
Traceback (most recent call last):
...
TypeError: function takes at most 8 arguments (9 given)
>>> d1.timetuple()
(2005, 1, 1, 12, 13, 10, 5, 1, -1)Because if I subclass datetime, I often need to convert between my subclass and
the built in datetime module. But there is no direct way to do it.
Instead I have to do it in a somewhat more clunky way:
>>> datetime(* (d1.timetuple()[:6] + (0, d1.tzinfo))) datetime.datetime(2005, 1, 1, 12, 13, 10)
if I want to convert a date to a datetime it is easy, even though I still have
to truncate the timetuple.
>>> d = date(2005, 1, 1) >>> datetime(*d.timetuple()[:6]) datetime.datetime(2005, 1, 1, 0, 0)
The other way around is also easy.
>>> dt = datetime(2005, 1, 1, 12, 0, 0) >>> date(*dt.timetuple()[:3]) datetime.date(2005, 1, 1)
But it's a clunky design that I have to do it that way.
I think it would be nice if date and datetime at least had a pair of
datetimetuple() and from_datetimetuple() methods that could be used for easily
converting between datetime types. Like the ones I have made below.
That would make them a lot more symmetric.
>>> datetimetuple = (2005,1,1,12,0,0,0,None) >>> datetime2.from_datetimetuple(datetimetuple) datetime2(2005, 1, 1, 12, 0)
>>> dtt = datetime2(2005,1, 1).datetimetuple() >>> dtt (2005, 1, 1, 0, 0, 0, 0, None)
>>> d2 = date2.from_datetimetuple(dtt) >>> d2 date2(2005, 1, 1)
>>> datetime2.from_datetimetuple(d2.datetimetuple()) datetime2(2005, 1, 1, 0, 0)
"""
from datetime import datetime, date
class datetime2(datetime):
def datetimetuple(self):
return self.timetuple()[:6] + (0, self.tzinfo) def from_datetimetuple(dt_tuple):
return datetime2(*dt_tuple)
from_datetimetuple = staticmethod(from_datetimetuple)
class date2(date):
def datetimetuple(self):
return self.timetuple()[:6] + (0, None) def from_datetimetuple(dt_tuple):
return date2(*dt_tuple[:3])
from_datetimetuple = staticmethod(from_datetimetuple)
#from datetime import datetime # #ical = Calendar() #print ical.ical()
if __name__ == "__main__":
import os.path, doctest, x
# import and test this file
doctest.testmod(x)
--
hilsen/regards Max M, Denmark
http://www.mxm.dk/ IT's Mad Science -- http://mail.python.org/mailman/listinfo/python-list
