[Python-Dev] datetime module enhancements (original) (raw)

Jon Ribbens jon+python-dev at unequivocal.co.uk
Sat Mar 10 14:29:09 CET 2007

Christian Heimes <lists at cheimes.de> wrote:

> What do you feel "next Tuesday plus 12 hours" means? ;-)

First thought: It's nonsense! Nobody would say that. ;) Second though: Tuesday noon (12h after the beginning of Tuesday)

I agree with you entirely. Your suggestions correspond to 'throw an exception' and 'return a datetime'. Note that in the second case you are agreeing with me that a date means midnight at the start of that date ;-)

Python datetime disagrees with us both. It basically says 'add the timedelta to midnight at the start of the date, then return just the date part of the result'.

I assume there is some reason for this surprising behaviour. But this is another example of where datetime is taking a pragmatic approach in an ambiguous situation - exactly as I am suggesting in the situation of comparing a date and a datetime.

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