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Groups > comp.lang.python > #63060

Re: need to print seconds from the epoch including the millisecond

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On 2014-01-03, Dave Angel <davea@davea.name> wrote:
> On Thu, 2 Jan 2014 16:23:22 +0000 (UTC), Grant Edwards 
><invalid@invalid.invalid> wrote:
>> AFAIK, that's irrelevent.  time.time() returns a float.  On all the
>> CPython implementations I know of, that is a 64-bit IEEE format, 
>> which provides 16 decimal digits of precision regardless of the 
>> granularity of the system time value.  At this point in time, that
>> means 10 digits left of the decimal point and 6 to the right.
>
> Correction: no more than about 6 to the right.  You can certainly get 
> less, from an os with a smaller resolution.

time.time() returns a Python float. A Python float will have 16 digits
of precision. Perhaps the OS always sets some of those digits to 0 (or
even random values), but they're still there.  Perhaps the accuracy or
granularity of the values returned is problematic on some OSes, but
the precision of the value doesn't change: there's no way he's "only
getting 2 decimal places" from time.time() unless (as you mention
below) he's printing them using a method that truncates/rounds.

> Or you can lose some of what you do get by printing in a sub-optimal
> way.

Yes, depending on how you print the value, you can hide some of the
digits.  But, there's no way for time.time() to return a value with
less than ~16 decimal digits of precicsion.

-- 
Grant Edwards               grant.b.edwards        Yow! !  Everybody out of
                                  at               the GENETIC POOL!
                              gmail.com            

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need to print seconds from the epoch including the millisecond matt.doolittle33@gmail.com - 2013-12-26 10:32 -0800
  Re: need to print seconds from the epoch including the millisecond Dan Stromberg <drsalists@gmail.com> - 2013-12-26 11:22 -0800
    Re: need to print seconds from the epoch including the millisecond matt.doolittle33@gmail.com - 2013-12-26 14:06 -0800
      Re: need to print seconds from the epoch including the millisecond Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-27 09:34 +1100
        Re: need to print seconds from the epoch including the millisecond Grant Edwards <invalid@invalid.invalid> - 2014-01-02 16:23 +0000
          Re: need to print seconds from the epoch including the millisecond Dave Angel <davea@davea.name> - 2014-01-02 21:41 -0500
            Re: need to print seconds from the epoch including the millisecond Grant Edwards <invalid@invalid.invalid> - 2014-01-03 15:33 +0000
              Re: need to print seconds from the epoch including the millisecond Chris Angelico <rosuav@gmail.com> - 2014-01-04 02:41 +1100
      Re: need to print seconds from the epoch including the millisecond Dave Angel <davea@davea.name> - 2013-12-26 17:48 -0500
      Re: need to print seconds from the epoch including the millisecond Terry Reedy <tjreedy@udel.edu> - 2013-12-26 20:03 -0500
      Re: need to print seconds from the epoch including the millisecond Roy Smith <roy@panix.com> - 2013-12-26 20:29 -0500
        Re: need to print seconds from the epoch including the millisecond matt.doolittle33@gmail.com - 2013-12-27 07:43 -0800
      Re: need to print seconds from the epoch including the millisecond Dave Angel <davea@davea.name> - 2013-12-26 23:54 -0500
        Re: need to print seconds from the epoch including the millisecond matt.doolittle33@gmail.com - 2013-12-27 07:42 -0800
        Re: need to print seconds from the epoch including the millisecond matt.doolittle33@gmail.com - 2013-12-27 07:40 -0800
          Re: need to print seconds from the epoch including the millisecond Dave Angel <davea@davea.name> - 2013-12-27 11:20 -0500
          Re: need to print seconds from the epoch including the millisecond Roy Smith <roy@panix.com> - 2013-12-27 11:27 -0500
            Re: need to print seconds from the epoch including the millisecond matt.doolittle33@gmail.com - 2013-12-27 10:09 -0800
              Re: need to print seconds from the epoch including the millisecond Roy Smith <roy@panix.com> - 2013-12-27 13:50 -0500
                Re: need to print seconds from the epoch including the millisecond Roy Smith <roy@panix.com> - 2013-12-27 13:53 -0500
                Re: need to print seconds from the epoch including the millisecond Roy Smith <roy@panix.com> - 2013-12-27 20:15 -0500
              Re: need to print seconds from the epoch including the millisecond Ned Batchelder <ned@nedbatchelder.com> - 2013-12-27 13:49 -0500
                Re: need to print seconds from the epoch including the millisecond matt.doolittle33@gmail.com - 2013-12-30 04:16 -0800
                Re: need to print seconds from the epoch including the millisecond Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-30 14:14 +0000
                Re: need to print seconds from the epoch including the millisecond Cousin Stanley <cousinstanley@gmail.com> - 2013-12-30 10:07 -0700
                Re: need to print seconds from the epoch including the millisecond Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-30 17:35 +0000
                Re: need to print seconds from the epoch including the millisecond Cousin Stanley <cousinstanley@gmail.com> - 2013-12-30 11:17 -0700
                Re: need to print seconds from the epoch including the millisecond Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-31 05:57 +1100
          Re: need to print seconds from the epoch including the millisecond Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-27 13:14 -0500
          Re: need to print seconds from the epoch including the millisecond Cameron Simpson <cs@zip.com.au> - 2013-12-28 11:25 +1100
            Re: need to print seconds from the epoch including the millisecond matt.doolittle33@gmail.com - 2013-12-29 18:44 -0800
              Re: need to print seconds from the epoch including the millisecond Ned Batchelder <ned@nedbatchelder.com> - 2013-12-30 07:50 -0500
                Re: need to print seconds from the epoch including the millisecond Roy Smith <roy@panix.com> - 2013-12-30 09:22 -0500
              Re: need to print seconds from the epoch including the millisecond Ned Batchelder <ned@nedbatchelder.com> - 2013-12-30 08:01 -0500
                Re: need to print seconds from the epoch including the millisecond matt.doolittle33@gmail.com - 2013-12-30 05:40 -0800
          Re: need to print seconds from the epoch including the millisecond Ned Batchelder <ned@nedbatchelder.com> - 2013-12-27 21:10 -0500
            Re: need to print seconds from the epoch including the millisecond Steven D'Aprano <steve@pearwood.info> - 2013-12-28 03:50 +0000

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