datetime: How to get diff between 2 dates in month units?

[Gustavo Niemeyer]

> I have a lot of monthly time series data.  I need to be able to compare
> two dates and get the number of months that they are apart.
[...]

If you can rely on external modules, you may use mx.DateTime for that.

> >>> d1 = datetime.date(2002,1,1)
> >>> d2 = datetime.date(2001,12,1)
> >>> diff = d1-d2
> >>> diff.days
> 31

This would be:

>>> d1 = DateTime.Date(2002,1,1)
>>> d2 = DateTime.Date(2001,12,1)
>>> diff = DateTime.RelativeDateDiff(d1,d2)
>>> diff.months
1

[...]
> >>>firstdate = newMonthlyDatetime(2002, 5)
> >>>Nov2002 = newMonthlyDatetime(2002, 11)
> >>>diff = Nov2002 - firstdate
> >>>diff.months
> 6

And this would be:

>>> firstdate = DateTime.Date(2002, 5)
>>> Nov2002 = DateTime.Date(2002, 11)
>>> diff = DateTime.RelativeDateDiff(Nov2002, firstdate)
>>> diff.months
6

-- 
Gustavo Niemeyer
http://niemeyer.net