On Tue, Jul 24, 2012 at 5:58 PM, Vincenzo Ampolo <vincenzo.amp...@gmail.com> wrote: > Hi all, > > This is the first time I write to this list so thank you for considering > this message (if you will) :)
You're welcome. > I know that this has been debated many times but until now there was no > a real use case. If you look on google about "python datetime > nanosecond" you can find more than 141k answer about that. They all say > that "you can't due to hardware imprecisions" or "you don't need it" > even if there is a good amount of people looking for this feature. Have you read PEP 410 and my rejection of it (http://mail.python.org/pipermail/python-dev/2012-February/116837.html)? Even though that's about using Decimal for timestamps, it could still be considered related. > But let me explain my use case: > > most OSes let users capture network packets (using tools like tcpdump or > wireshark) and store them using file formats like pcap or pcap-ng. These > formats include a timestamp for each of the captured packets, and this > timestamp usually has nanosecond precision. The reason is that on > gigabit and 10 gigabit networks the frame rate is so high that > microsecond precision is not enough to tell two frames apart. > pcap (and now pcap-ng) are extremely popular file formats, with millions > of files stored around the world. Support for nanoseconds in datetime > would make it possible to properly parse these files inside python to > compute precise statistics, for example network delays or round trip times. > > More about this issue at http://bugs.python.org/issue15443 > > I completely agree with the YAGNI principle that seems to have driven > decisions in this area until now but It is the case to reconsider it > since this real use case has shown up? Not every use case deserves an API change. :-) First you will have to show how you'd have to code this *without* nanosecond precision in datetime and how tedious that is. (I expect that representing the timestamp as a long integer expressing a posix timestamp times a billion would be very reasonable.) I didn't read the entire bug, but it mentioned something about storing datetimes in databases. Do databases support nanosecond precision? -- --Guido van Rossum (python.org/~guido) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
