implementing a calendar class

[python101]

Following is a class that does not use Python's datetime module:[code=Python]...
[/code]

It is a little complicated and It seems that there is something I don't know. Like I never read something that when defining a method, we don't use self._something

assume that I have self._month, self._day, self._year has been property defined.
I have two list of maximum day for regular year and leap year.
I would like to write a nextDate() method to increase one day of current date, how can I write it?

[code=python]
class CalculationDate :
daysList1 = [31,28,31,30,31, 30,31,31,30,31, 30,31]
daysList2 = [31,29,31,30,31, 30,31,31,30,31, 30,31]
def __ini__(m, d, yr):
self._month...
self._day...
self._year... # all of these things are written properly if user enters invalid information date, it will ask to change the date.
#now I would like to have a nextDay method:
def nextDay(self):
# how can I write this
[/code]

[bvdet]

It is a little complicated and It seems that there is something I don't know. Like I never read something that when defining a method, we don't use self._something

assume that I have self._month, self._day, self._year has been property defined.
I have two list of maximum day for regular year and leap year.
I would like to write a nextDate() method to increase one day of current date, how can I write it?

[code=python]
class CalculationDate :
daysList1 = [31,28,31,30,31, 30,31,31,30,31, 30,31]
daysList2 = [31,29,31,30,31, 30,31,31,30,31, 30,31]
def __ini__(m, d, yr):
self._month...
self._day...
self._year... # all of these things are written properly if user enters invalid information date, it will ask to change the date.
#now I would like to have a nextDay method:
def nextDay(self):
# how can I write this
[/code]

The use of a leading underscore is for variables and methods intended to be non-public. I seldom make variables and methods non-public in the applications I have developed.

Did you notice that I included a nextDay() method in my post? The key is in the __add__(), monthDayYr(), and dayNo() methods. Method dayNo() returns the day number in the current year and does input validation on the day of the month. Method monthDayYr() returns a month, day, year tuple given a number of days with respect to the current year. Example:
[code=Python]>>> print a
June 8, 2007
>>> a.monthDayYr(a. dayNo())
(6, 8, 2007)
>>> a.monthDayYr(1)
(1, 1, 2007)
>>> a.monthDayYr(20 000)
(10, 3, 2061)
>>> a.dayNo()
159
>>> [/code]Method __add__() returns a Dates() object:[code=Python]....def __add__(self, days):
return Dates('/'.join([str(item) for item in self.monthDayYr (self.dayNo() + days)]))[/code]The method nextDay() is now very simple:[code=Python]....def nextDay(self):
return self+1[/code][code=Python]>>> print d
December 31, 2000
>>> d.nextDay()
<__main__.Dat es object at 0x00DC70B0>
>>> print d.nextDay()
January 1, 2001
>>> [/code]Following is an example using a Dates() object to parse the input and the Python datetime module:[code=Python]if __name__ == '__main__':
import datetime
d = Dates('6/8/2007')
dt = datetime.dateti me(d.year, d.month, d.day)
oneday = datetime.timede lta(days=1)
newdate = dt + oneday
print newdate[/code]Output: >>> 2007-06-09 00:00:00

HTH