Difference Between Two datetimes

[W. eWatson]

Ben Finney wrote:
> "W. eWatson" <wolftracks at invalid.com> writes:
> 
>> Lie Ryan wrote:
>>> what's strange about it? the difference between 2009/01/02 13:01:15
>>> and 2009/01/04 13:01:15 is indeed 2 days... Can you elaborate what
>>> do you mean by 'strange'?
> 
>> Easily. In one case, it produces a one argument funcion, and the other
>> 2, possibly even a year if that differs.
> 
> In both cases it produces not a function, but a ‘datetime.timedelta’
> object::
> 
>     >>> import datetime
>     >>> t1 = datetime.datetime(2009, 1, 2, 13, 1, 15)
>     >>> t2 = datetime.datetime(2009, 1, 4, 13, 1, 15)
>     >>> type(t1)
>     <type 'datetime.datetime'>
>     >>> type(t2)
>     <type 'datetime.datetime'>
> 
>     >>> dt = (t2 - t1)
>     >>> type(dt)
>     <type 'datetime.timedelta'>
> 
> What you're seeing in the interactive interpreter is a string
> representation of the object::
> 
>     >>> dt
>     datetime.timedelta(2)
> 
> This is no different from what's going on with any other string
> representation. The representation is not the value.
> 
>> How does one "unload" this structure to get the seconds and days?
> 
> It's customary to consult the documentation for questions like that
> <URL:http://docs.python.org/library/datetime.html#datetime.timedelta>.
> 
>> To find the difference more clearly. Why not just return (0,2,3555)
> 
> Because the ‘datetime.timedelta’ type is more flexible than a tuple, and
> has named attributes as documented at the above URL::
> 
>     >>> dt.days
>     2
>     >>> dt.seconds
>     0
>     >>> dt.microseconds
>     0
> 
Well, it just seems weird to me. <g>. I'm modestly familiar with 
objects, but this seems like doing the following.

Suppose we have a module called trigonometry, trig for short. It 
contains lots of trig functions, and sort of uses the same concepts as 
datetime. Bear with me on that. Here's my imagined interpretive session:

 >> import trig
 >> c=trig.sin(90.0) # arg is in degrees
 >> print c
trig.cos(1.0)
 >> type(c)
<type 'trig'>
 >> value = c.value
 >> print value
1.0
I'd call that weird. Maybe in this case it is ... <g>