Re: [Matplotlib-users] Format date tick labels

[Damon M. <dam...@gm...>]

On Thursday, October 11, 2012, Benjamin Root wrote:

>
>
> On Thu, Oct 11, 2012 at 4:53 PM, Mark Lawrence <bre...@ya...<javascript:_e({}, 'cvml', 'bre...@ya...');>
> > wrote:
>
>> On 11/10/2012 10:55, Damon McDougall wrote:
>> > On Wed, Oct 10, 2012 at 5:00 PM, Benjamin Root <ben...@ou...<javascript:_e({}, 'cvml', 'ben...@ou...');>>
>> wrote:
>> >>
>> >>
>> >> On Wed, Oct 10, 2012 at 10:55 AM, Mark Lawrence <
>> bre...@ya... <javascript:_e({}, 'cvml',
>> 'bre...@ya...');>>
>> >> wrote:
>> >>>
>> >>> On 10/10/2012 15:41, Mark Lawrence wrote:
>> >>>> On 10/10/2012 14:29, Benjamin Root wrote:
>> >>>>>
>> >>>>> I know of a few people who have difficulties with matplotlib's
>> datetime
>> >>>>> handling, but they are usually operating on the scale of
>> milliseconds
>> >>>>> or
>> >>>>> less (lightning data), in which case, one is already at the edge of
>> the
>> >>>>> resolution handled by python's datetime objects.  However, we would
>> >>>>> certainly welcome any sort of examples of how matplotlib fails in
>> >>>>> handling
>> >>>>> seconds scale and lower plots.
>> >>>>>
>> >>>>> Cheers!
>> >>>>> Ben Root
>> >>>>>
>> >>>>>
>> >>>>
>> >>>> I'll assume that the milliseconds above is a typo.  From
>> >>>> http://docs.python.org/library/datetime.html "class
>> datetime.timedelta A
>> >>>> duration expressing the difference between two date, time, or
>> datetime
>> >>>> instances to microsecond resolution."  Still, what's a factor of 1000
>> >>>> amongst friends? :)
>> >>>>
>> >>>
>> >>> http://www.python.org/dev/peps/pep-0418/ has been implemented in
>> Python
>> >>> 3.3 and talks about clocks with nanosecond resolutions.  I've flagged
>> it
>> >>> up here just in case people weren't aware.
>> >>>
>> >>
>> >> Ah, you are right, I meant microseconds.
>> >>
>> >> With apologies to Spaceballs:
>> >>
>> >> "Prepare to go to microsecond resolution!"
>> >> "No, no, microsecond resolution is too slow"
>> >> "Microsecond resolution is too slow?"
>> >> "Yes, too slow. We must use nanosecond resolution!"
>> >> "Prep-- Prepare Python, for nanosecond resolution!"
>> >>
>> >> Cheers!
>> >> Ben Root
>> >
>> > Am I missing something here? Are seconds just floats internally? A
>> > delta of 1e-6 is nothing (pardon the pun). A delta of 1e-9 is the
>> > *least* I'd expect. Maybe even 1e-12. Perhaps the python interpreter
>> > doesn't do any denormalising<
>> http://stackoverflow.com/questions/9314534/why-does-changing-0-1f-to-0-slow-down-performance-by-10x
>> >
>> > when encountered with deltas very close to zero...
>> >
>>
>> What percentage of computer users wants a delta of 1e-12?  I suspect
>> that the vast majority of users couldn't care two hoots about miniscule
>> time deltas in a world where changing time zones can cause chaos.  Where
>> some applications cannot handle years before 1970, or 1904, or 1900 or
>> whatever.  Or they can't go too far forward, 2036 I think but don't
>> quote me.  Where people like myself had to put a huge amount of effort
>> into changing code so that applications would carry on working when the
>> date flipped over from 31st December 1999 to 1st January 2000.  If
>> things were that simple why is matplotlib using third party modules like
>> dateutil and pytz?  Why doesn't the "batteries included" Python already
>> provide this functionality?
>>
>>
> Preach on, my brother! Preach on!
>
> [psst -- you are facing the choir...]
>
> Cheers!
> Ben Root
>
>
Clearly I have misunderstood something and hit a nerve. Apologies.


-- 
Damon McDougall
http://www.damon-is-a-geek.com
B2.39
Mathematics Institute
University of Warwick
Coventry
West Midlands
CV4 7AL
United Kingdom