>class DateTime(datetime.datetime): > def __init__(self, year, month, day, *args): > super().__init__() > if self.year >= 1000: > self.year = self.year % 1000
I have no idea how you could use the sample you have given (or why) but, this was actually a fun exercise that forced me to learn more about immutable types (which makes sense because a date should never really be modifiable if you think about it). Instead of overriding the __init__ you need to override the __new__ method. Try the following >>> class DateTime(datetime.datetime): ... def __new__(self, year, month, day, *args): ... if year >= 1000: ... year = year % 1000 ... return super( DateTime, self ).__new__(self, year, month, day, *args ) ... >>> DateTime( 2011, 1, 1 ) DateTime(11, 1, 1, 0, 0) Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 -- From: tutor-bounces+ramit.prasad=jpmorgan....@python.org [mailto:tutor-bounces+ramit.prasad=jpmorgan....@python.org] On Behalf Of rail shafigulin Sent: Friday, December 09, 2011 4:15 PM To: tutor@python.org Subject: Re: [Tutor] attribute overwrite On Fri, Dec 9, 2011 at 4:43 PM, rail shafigulin <rail.shafigu...@gmail.com> wrote: i need to overwrite and attribute from the inherited class. i also need to run the constructor of the super class. here is the code import datetime class DateTime(datetime.datetime): def __init__(self, year, month, day, *args): super().__init__(year, month, day, *args) if self.year >= 1000: self.year = self.year % 1000 i'm getting the following error: AttributeError: attribute 'year' of datetime.datetime objects are not writable. some of you might suggest to change self.year = self.year % 1000 to self.yr = self.year % 1000 but i'd need to keep the name the same. any help is appreciated. my apologies, but there is a minor mistake in the code: import datetime class DateTime(datetime.datetime): def __init__(self, year, month, day, *args): super().__init__() if self.year >= 1000: self.year = self.year % 1000 def main(): mytme = DateTime.now() if __name__ == '__main__' main() This email is confidential and subject to important disclaimers and conditions including on offers for the purchase or sale of securities, accuracy and completeness of information, viruses, confidentiality, legal privilege, and legal entity disclaimers, available at http://www.jpmorgan.com/pages/disclosures/email. _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
