Re: [Python-Dev] proposal: add basic time type to the standard library
Jim Fulton wrote:
"M.-A. Lemburg" wrote:
Jim Fulton wrote:
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What is data roundtrip safety?
Roundtrip safety means that e.g. if you take a COM date value from a ADO and create a DateTime object with it, you can be sure to get back the exact same value via the COMDate() method.
Since I don't know what COMDate is, this doesn't mean anything to me. :)
Then you're lucky -- COMDates are just about the strangest beast I've ever seen as date/time encoding.
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I suppose that I could easily make a few calculation lazy to enhance speed; memory footprint would not change though. It's currently at 56 bytes per DateTime object and 36 bytes per DateTimeDelta object.
Does that include the two words of Python object overhead?
I suppose so -- the values I quoted are the tp_size values of the types. The instance will probably also require a dictionary and the weak ref list on top of those figures.
To get similar accuracy in Python,
I assume you mean precision.
Eh, yes.
you'd need a float and an integer per object,
It depends on the desired precision. To get minute precision, an int will do. Two ints can get you about a hundreth of a microsecond precision, which is more than most people need.
I was just trying to compare apples to apples :-) mxDateTime offers the same precision as a float (for daytime) and an integer (for the day) can give.
that's 16 bytes + 12 bytes == 28 bytes + malloc() overhead for the two and the wrapping instance which gives another 32 bytes (provided you store the two objects in slots)... >60 bytes per Python based date time object.
A Python-based date-time object isn't very interesting to me.
You should have mentioned that earlier ;-) -- Marc-Andre Lemburg CEO eGenix.com Software GmbH ______________________________________________________________________ Company & Consulting: http://www.egenix.com/ Python Software: http://www.egenix.com/files/python/
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M.-A. Lemburg