sub-classing the types in the builtin module datetime

[Colin J. Williams]

I wish to sub-class (if that's the right word) datetime and to use a
different signature for the constructor.

The second part has gone smoothly, but it is difficult to access the
type's methods from the sub-class instance.

I'm beginning to wonder whether it might might be simpler to write my
own Date class.

Does anyone have any comments please?

Colin W.

[Michael Amrhein]

Colin J. Williams wrote:

I wish to sub-class (if that's the right word) datetime and to use a
different signature for the constructor.

The second part has gone smoothly, but it is difficult to access the
type's methods from the sub-class instance.

What's difficult?

>>from datetime import datetime
class mydt(datetime): pass

....

>>dt=mydt(2007,8,15)
dt.day

15

>>dt.now()

mydt(2007, 8, 15, 18, 57, 58, 562000)

How did you overwrite the constuctor?
Are you sure your constructor really returns a subclass of datetime?

I'm beginning to wonder whether it might might be simpler to write my
own Date class.

If you only want to change the signature of the constuctor, just write a
factory function.

Does anyone have any comments please?

Colin W.

Have fun,
Michael