nptime 1.1

Extends datetime.time, allowing time arithmetic

Python’s “datetime” module has many uses, but it has a difficulty: you can’t do any arithmetic with “datetime.time”. Only with “datetime.datetime”. Now, there are good reasons for this: “What time will it be, 24 hours from now” has a lot of corner cases, including daylight savings time, leap seconds, historical timezone changes, and so on. But sometimes you really do need the simple case. Sometimes the perfect is the enemy of the good. And that’s why you have this module. This module will allow you to cocoon yourself in the comforting illusion that, in 24 hours, it will be the same time as it is right now.

And what freedom this illusion gives you! You can add a “datetime.timedelta” object to an “nptime” object, and it works! It will cycle around 24 hours, like modular arithmetic. You can ask “what time comes 1 day and 36 minutes after 12:24 pm?” and it will let you know: 1:00 pm. How lovely!

>>> from nptime import nptime
>>> from datetime import timedelta, date, datetime
>>> afternoon = nptime(12, 24) + timedelta(days=1, minutes=36)
>>> afternoon
nptime(13, 0)
>>> str(afternoon)
'13:00:00'

Maybe we’re talking about the afternoon of Guido van Rossum’s birthday. Lucky, we can combine “nptime” objects with “date” objects:

>>> datetime.combine(date(1956, 1, 31), afternoon)
datetime.datetime(1956, 1, 31, 13, 0)

You can also ask “How long is it between 9:00 AM and 5:00 PM? It sure feels like a million years!”

>>> workday = nptime(hour=17) - nptime(hour=9)
>>> workday
datetime.timedelta(0, 28800)
>>> print(workday)
8:00:00

Nope, only 8 hours, how strange. Anyway, please use this module. It will be convenient. But don’t use it when talking about concrete time, time in a particular place, or anything like that. In fact, it doesn’t even notice “datetime.tzinfo” objects right now. Good luck.

Note: You can find the newest version at

https://github.com/tgs/nptime . You can find online documentation at http://tgs.github.com/nptime/ . The package is available for download from PyPi: easy_install nptime. This software is licensed under the 3-clause BSD License.