[Python-Dev] Interop between datetime and mxDateTime (original) (raw)

Tim Peters tim.one@comcast.net
Mon, 13 Jan 2003 13:46:05 -0500

[Fredrik Lundh]

the last revision of the "time type" proposal seems to suggest that all time types should implement the following interface:

Calling T datetime.time, and D datetime.datetime:

tm = timeobject.timetuple()

D yes, T no.

cmp(timeobject, timeobject)

Both yes, but not a mix of D and T.

hash(timeobject)

Both yes.

It's curious that that the minimal API doesn't have a way to create a timeobject ab initio (the only operations here with a timeobject output need a timeobject as input first).

and optionally

deltaobject = timeobject - timeobject

D yes, T no.

floatobject = float(deltaobject) # fractional seconds

datetime.timedelta doesn't have anything like that, but it could be useful. Converting a timedelta to minutes (or seconds, or whatever) is painful now. I'd rather see explicit .toseconds(), .tominutes() (etc) methods. A caution that an IEEE double doesn't necessariy have enough bits of precision so that roundrip equality can be guaranteed. I expect you'd also need an API to create a delta object from a number of seconds (in datetime that's spelled

datetime.timedelta(seconds=a_float_int_or_long)

).

timeobject = timeobject + integerobject

Neither, and unclear what it means (is the integer seconds? milliseconds? days? etc).

timeobject = timeobject + floatobject

Neither, likewise.

timeobject = timeobject + deltaobject

D yes, T no.