CODEWITHSUNDEEP
python
Him
Him

Reputation: 5549

replacing return types of class methods with inherited class

I'm extending the datetime object because I would like to override the str method. 

class MyDatetime(datetime.datetime):
    def __str__(self):
        return self.strftime("%Y-%m-%dT%H:%M:%S.%fZ")

problem, is that whenever I start adding and subtracting timedeltas, I get back datetimes and not MyDatetimes. I could include a constructor for a MyDatetime from a datetime and then override the __add__ and __sub__ methods as well, but there could be others, and it just seems like there should be some easy way to deal with this... Any suggestions?

Upvotes: 2

Views: 49

Answers (1)

Lav
Lav

Reputation: 2274

There is no easy way in your situation - you'll have to override all mathematical magic methods if you want to cover all possible situations.

There's a comprehensive list of mathematical magic methods in Python documentation:

https://docs.python.org/2.7/reference/datamodel.html#emulating-numeric-types

At least the code for those methods will be similar enough so you should be able to create them by lots of copy&paste with minor modifications.

Upvotes: 1

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