Re: YADTR (Yet Another DateTime Rant)

References	<roy-142548.20582725032014@news.panix.com> <mailman.8575.1395841035.18130.python-list@python.org> <1102ec6b-6205-40f4-bb7c-d40f9d13115b@googlegroups.com>
Date	2014-03-26 10:39 -0500
Subject	Re: YADTR (Yet Another DateTime Rant)
From	Skip Montanaro <skip@pobox.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.8581.1395848399.18130.python-list@python.org> (permalink)

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On Wed, Mar 26, 2014 at 10:04 AM, Roy Smith <roy@panix.com> wrote:
> No, what you said was "negative four days, positive 3605 seconds".

My apologies for not showing all my work, professor. I use datetime
and timedelta objects all the time. I did the arithmetic to go from
3605 to one hour, five minutes in my head.

The point of my post was that there is no obvious one best way to
present negative timedeltas in a human readable form. In my usage it's
not generally a big deal, as most of the time I want to display
datetime objects. In your case, it's obviously a problem. If Tim
thought that timedelta objects would be presented to users as a
regular course of doing business, maybe he would have given them a
strftime() method. I suggest you write a function to format it the way
you want and be done with it.

You might consider taking a crack at a strftime() (and strptime?)
implementation for timedelta objects that uses the ISO 8601 notation
and submit it as a patch for datetimemodule.c. Note though, that the
ISO8601 representation isn't without its own flaws (which might
explain why Tim avoided it BITD):

* It doesn't appear to provide a way to represent fractions of a
second (though perhaps all the fields can be fractional)
* How many days are in a month or a year? (It has format codes for
both. Writing a useful strptime is probably impossible.)
* It has other ambiguities ("M" represents both months and minutes -
what were they thinking?)

Skip

Thread

YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-25 20:58 -0400
  Re: YADTR (Yet Another DateTime Rant) Ethan Furman <ethan@stoneleaf.us> - 2014-03-25 18:19 -0700
  Re: YADTR (Yet Another DateTime Rant) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-26 09:27 +0000
  Re: YADTR (Yet Another DateTime Rant) Skip Montanaro <skip@pobox.com> - 2014-03-26 08:37 -0500
    Re: YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-26 08:04 -0700
      Re: YADTR (Yet Another DateTime Rant) Skip Montanaro <skip@pobox.com> - 2014-03-26 10:39 -0500
        Re: YADTR (Yet Another DateTime Rant) Marko Rauhamaa <marko@pacujo.net> - 2014-03-26 17:58 +0200
          Re: YADTR (Yet Another DateTime Rant) Skip Montanaro <skip@pobox.com> - 2014-03-26 11:34 -0500
            Re: YADTR (Yet Another DateTime Rant) Marko Rauhamaa <marko@pacujo.net> - 2014-03-26 19:13 +0200
            Re: YADTR (Yet Another DateTime Rant) Grant Edwards <invalid@invalid.invalid> - 2014-03-26 19:12 +0000
              Re: YADTR (Yet Another DateTime Rant) Ben Finney <ben+python@benfinney.id.au> - 2014-03-27 07:06 +1100
      Re: YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-26 11:50 -0400
  Re: YADTR (Yet Another DateTime Rant) Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2014-03-26 15:02 +0100
    Re: YADTR (Yet Another DateTime Rant) Marko Rauhamaa <marko@pacujo.net> - 2014-03-26 16:43 +0200
  Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-27 01:12 +1100
    Re: YADTR (Yet Another DateTime Rant) Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-03-27 11:08 +1300
  Re: YADTR (Yet Another DateTime Rant) Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-03-26 19:25 -0400
    Re: YADTR (Yet Another DateTime Rant) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-27 00:16 +0000
      Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-27 12:28 +1100
        Re: YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-26 21:38 -0400
          Re: YADTR (Yet Another DateTime Rant) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-27 08:40 +0000
      Re: YADTR (Yet Another DateTime Rant) Dan Sommers <dan@tombstonezero.net> - 2014-03-27 03:56 +0000
      Re: YADTR (Yet Another DateTime Rant) Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-03-27 11:22 +0100
        Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-27 21:44 +1100
          Re: YADTR (Yet Another DateTime Rant) Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-03-27 12:05 +0100
            Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-27 22:33 +1100
          Re: YADTR (Yet Another DateTime Rant) Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-03-27 12:25 +0100
            Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-27 22:42 +1100
            Re: YADTR (Yet Another DateTime Rant) Skip Montanaro <skip@pobox.com> - 2014-03-27 06:56 -0500
              Re: YADTR (Yet Another DateTime Rant) Marko Rauhamaa <marko@pacujo.net> - 2014-03-27 16:04 +0200
            Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-27 23:20 +1100
            Re: YADTR (Yet Another DateTime Rant) Skip Montanaro <skip@pobox.com> - 2014-03-27 08:01 -0500
            Re: YADTR (Yet Another DateTime Rant) Terry Reedy <tjreedy@udel.edu> - 2014-03-27 17:10 -0400
            Re: YADTR (Yet Another DateTime Rant) Ethan Furman <ethan@stoneleaf.us> - 2014-03-27 17:04 -0700
            Re: YADTR (Yet Another DateTime Rant) Terry Reedy <tjreedy@udel.edu> - 2014-03-27 21:46 -0400
              Re: YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-27 21:59 -0400
                Re: YADTR (Yet Another DateTime Rant) Terry Reedy <tjreedy@udel.edu> - 2014-03-27 22:24 -0400
                Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-28 14:03 +1100
          Re: YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-27 08:52 -0400
            Re: YADTR (Yet Another DateTime Rant) Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2014-03-27 15:12 +0100
            Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-28 01:15 +1100
            Re: YADTR (Yet Another DateTime Rant) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-27 23:41 +0000
              Re: YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-27 20:29 -0400
                Re: YADTR (Yet Another DateTime Rant) Ben Finney <ben+python@benfinney.id.au> - 2014-03-28 11:43 +1100
                Re: YADTR (Yet Another DateTime Rant) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-28 11:11 +0000
                Re: YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-28 08:30 -0400
                Re: YADTR (Yet Another DateTime Rant) Marko Rauhamaa <marko@pacujo.net> - 2014-03-28 15:10 +0200
                Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-29 00:19 +1100
                Re: YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-28 09:22 -0400
                Re: YADTR (Yet Another DateTime Rant) Rustom Mody <rustompmody@gmail.com> - 2014-03-28 06:30 -0700
                Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-29 00:32 +1100
                Re: YADTR (Yet Another DateTime Rant) Roy Smith <roy@panix.com> - 2014-03-28 09:20 -0400
                Re: YADTR (Yet Another DateTime Rant) Marko Rauhamaa <marko@pacujo.net> - 2014-03-28 16:34 +0200
                Re: YADTR (Yet Another DateTime Rant) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-28 14:35 +0000
                Re: YADTR (Yet Another DateTime Rant) Chris Angelico <rosuav@gmail.com> - 2014-03-29 02:25 +1100
  Re: YADTR (Yet Another DateTime Rant) Ethan Furman <ethan@stoneleaf.us> - 2014-03-26 16:33 -0700

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