[Python-Dev] redux: fractional seconds in strptime

[Skip Montanaro]

    >> I realize the %4N notation is distasteful, but without it I think you
    >> will have trouble parsing something like
    >> 
    >> 13:02:00.704
    >> 
    >> What would be the format string?  %H:%M:%S.%N would be incorrect.

    Brett> Why is that incorrect?

Because "704" represents the number of milliseconds, not the number of
nanoseconds.

I'm sure that in some applications people are interested in extremely short
time scales.  Writing out hours, minutes and seconds when all you are
concerned with are small fractions of seconds (think high energy physics)
would be a waste.  In those situations log entries like

    704 saw proton
    705 proton hit neutron
    706 saw electron headed toward Saturn

might make perfect sense.  Parsing the time field entirely within
time.strptime would be at least clumsy if you couldn't tell it the scale of
the numbers you're dealing with.  Parsing with %N, %3N or %6N would give
different values (nanoseconds, milliseconds or microseconds).

Skip