On Wed, 6 Sep 2006, Rimantas Liubertas wrote:

> <...>
>> >>> delta = b - a
>> > => 42.0
>> >>> p delta.days
>> > 3628800.0
>> > => nil
>> 
>> right.  that is totally wrong.  the difference is only 42 seconds, therefor 
>> it
>> should be a fractional day.  eg.
> <...>
>
> 'days' and similar methods in Rails are core extensions and return
> number of seconds.
> So 42.days returns number of seconds in 42 days.
>
> Useful for things like:
>
>>> 10.minutes.ago
> => Wed Sep 06 12:56:52 FLE Daylight Time 2006
>>> 3.days.since
> => Sat Sep 09 13:06:58 FLE Daylight Time 2006

thanks, i realize that.  this little extension does both:

     harp:~ > cat a.rb
     require 'timeunits'

     a = Time.now.utc

     b = a + 42.days  # like rails, facets, etc.

     p a
     p b

     delta = b - a
     p delta.days     # inverse operation


     harp:~ > ruby a.rb
     Wed Sep 06 14:23:29 UTC 2006
     Wed Oct 18 14:23:29 UTC 2006
     42.0

not that computing 'days' on a difference is the inverse operation (/) as
compared to when doing in a summation  ('*').

regards.

-a
-- 
what science finds to be nonexistent, we must accept as nonexistent; but what
science merely does not find is a completely different matter... it is quite
clear that there are many, many mysterious things.
- h.h. the 14th dalai lama