[R] Milisecond problem in as.POSIXct ?

[Joshua Ulrich]

This is known behavior with how POSIXt objects are printed.  See the
discussion on StackOverflow:
http://stackoverflow.com/questions/7726034/how-r-formats-posixct-with-fractional-seconds

On Wed, Jun 10, 2015 at 7:41 PM, ce <zadig_1 at excite.com> wrote:

> Dear all,
>
> my main problem is with miliseconds. I have an array :
>
> library(xts)
> options(digits.secs = 3)
> > x
> [1] "2015-06-10 10:22:06.389 EDT" "2015-06-10 10:22:07.473 EDT"
> [3] "2015-06-10 10:22:08.717 EDT" "2015-06-10 10:22:09.475 EDT"
>
> > x[1]
> [1] "2015-06-10 10:22:06.38 EDT"
> > x[2]
> [1] "2015-06-10 10:22:07.473 EDT"
>
> why it cuts last digit of miliseconds 389 to 38 ? ( it doesn't cut 473 !! )
>
> I try to dump it to post here:
>
> > dump("x",file=stdout())
>
> x <-
> structure(c(1433946126.39, 1433946127.474, 1433946128.717, 1433946129.476
> ), tzone = "", tclass = c("POSIXct", "POSIXt"), class = c("POSIXct",
> "POSIXt"))
>
> new array becomes :
>
> > x
> [1] "2015-06-10 10:22:06.390 EDT" "2015-06-10 10:22:07.473 EDT"
> [3] "2015-06-10 10:22:08.717 EDT" "2015-06-10 10:22:09.476 EDT"
>
> this time first milisecond 389 became 390 ?  and last element 475 became
> 476 ?
>
> I do some more tests :
>
> as.POSIXct("2015-06-10 10:22:07.473",format='%Y-%m-%d %H:%M:%OS')
> [1] "2015-06-10 10:22:07.473 EDT"
>
> is correct, but :
>
> as.POSIXct("2015-06-10 10:22:06.389",format='%Y-%m-%d %H:%M:%OS')
> [1] "2015-06-10 10:22:06.388 EDT"
>
> why miliseconds turn to 388 instead of 389 ?
>
> or
>
>  as.POSIXct("2015-06-10 10:22:07.478",format='%Y-%m-%d %H:%M:%OS')
> [1] "2015-06-10 10:22:07.477 EDT"
>
>  why it shows 477 instead of 478
>
> > sessionInfo()
> R version 3.2.0 (2015-04-16)
> Platform: x86_64-suse-linux-gnu (64-bit)
> Running under: openSUSE 13.2 (Harlequin) (x86_64)
>
> locale:
>  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
>  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
>  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
>  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
>  [9] LC_ADDRESS=C               LC_TELEPHONE=C
> [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> other attached packages:
> [1] xts_0.9-7  zoo_1.7-12
>
> loaded via a namespace (and not attached):
> [1] tools_3.2.0     grid_3.2.0      lattice_0.20-31
>
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>



-- 
Joshua Ulrich  |  about.me/joshuaulrich
FOSS Trading  |  www.fosstrading.com

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