peter wrote: > On Nov 25, 3:46 pm, Peter Otten <[EMAIL PROTECTED]> wrote: >> peter wrote: >> >>>> import datetime >> >>>> class ts(datetime.datetime): >> > ... foo = 'bar' >> > ... def __new__(cls, s): >> > ... c = super(ts, cls) >> > ... return c.fromtimestamp(s) >> > ... >> >>>> t = ts(0) >> > Traceback (most recent call last): >> > File "<stdin>", line 1, in <module> >> > File "<stdin>", line 5, in __new__ >> > TypeError: __new__() takes exactly 2 arguments (9 given) >> >> > I don't understand why that happens -- am I correct in assuming that >> > the call to .fromtimestamp() is picking up on the ts class? Shouldn't >> > it get the datetime class instead? >> >> > (Yes, I am aware of the problems of using datetime and timestamps) >> >> > Could some kind soul please enlighten me? >> >> If the datetime class were implemented in Python the fromtimestamp() >> method could look like: >> >> @classmethod >> def fromtimestamp(cls, s): >> year, month, day,... = ... >> return cls(year, month, day,...) >> >> This will fail since you modified the constructor to accept only a single >> argument. > > Hm, I had hoped that using super() would result in calling the > constructor of the superclass, ie. datetime. Did I use super() wrong? > > Thanks, > peter.
Sorry, I didn't pay the necessary attention. I've only used super() with "normal" methods, but as >>> from datetime import * >>> class TS(datetime): ... def __new__(cls, ts): ... return datetime.fromtimestamp(ts) ... >>> TS(0) datetime.datetime(1970, 1, 1, 1, 0) works super() would be the most likely culprit. Peter -- http://mail.python.org/mailman/listinfo/python-list
