[R] How to deal with thousands of seconds in R?
Prof Brian Ripley
ripley at stats.ox.ac.uk
Tue Oct 9 14:51:24 CEST 2012
On 09/10/2012 09:54, Agustin Lobo wrote:
> If I do:
>> a
> [1] "2012_10_01_14_13_32.445"
>> a2
> [1] "2012_10_01_14_13_32.500"
>> strptime(a,format="%Y_%M_%d_%H_%M_%S")-strptime(a2,format="%Y_%M_%d_%H_%M_%S")
> Time difference of 0 secs
>
> Is there any time object in R that would deal with thousands of seconds?
Did you mean milliseconds, that is 1/1000th of a second? If so, see the
help for the function you used:
‘%S’ Second as decimal number (00-61), allowing for up to two
leap-seconds (but POSIX-compliant implementations will ignore
leap seconds).
Specific to R is ‘%OSn’, which for output gives the seconds
truncated to ‘0 <= n <= 6’ decimal places (and if ‘%OS’ is not
followed by a digit, it uses the setting of
‘getOption("digits.secs")’, or if that is unset, ‘n = 3’).
Further, for ‘strptime’ ‘%OS’ will input seconds including
fractional seconds. Note that ‘%S’ ignores (and not rounds)
fractional parts on output.
strptime(a,format="%Y_%M_%d_%H_%M_%OS")-strptime(a2,format="%Y_%M_%d_%H_%M_%OS")
Time difference of -0.05500007 secs
(Note that a is not a binary fraction, so some representation error is
expected.)
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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