Dear R-helpers,
can I use a POSIXct date as the x variable in interpSpline? The help
page says x and y need to be numeric... is there a workaround?
example:
library(splines)
testdfr <-
data.frame(Date=seq(as.POSIXct("2008-08-01"),as.POSIXct("2008-09-01"),
length=10))
testdfr$yvar <- rnorm(10)
sp <- interpSpline(yvar ~ Date, testdfr)
preddfr <- data.frame(Date=as.POSIXct("2008-08-02"))
predict(sp, preddfr)
thanks,
Remko
-------------------------------------------------
Remko Duursma
Post-Doctoral Fellow
Centre for Plant and Food Science
University of Western Sydney
Hawkesbury Campus
Richmond NSW 2753
Dept of Biological Science
Macquarie University
North Ryde NSW 2109
Australia
Mobile: +61 (0)422 096908
It certainly appears that you just _did_ use it as such. You got a
spline. The only error thrown was from predict() and I think that was
because you needed to use a bit of extra coercion.
> predict(sp, x=as.numeric(as.POSIXct("2008-08-02")))
$x
[1] 1217649600
$y
[1] -0.4748701
attr(,"class")
[1] "xyVector"
--
David Winsemius
On Feb 25, 2009, at 9:30 PM, Remko Duursma wrote:
> Dear R-helpers,
>
> can I use a POSIXct date as the x variable in interpSpline? The help
> page says x and y need to be numeric... is there a workaround?
>
> example:
>
> library(splines)
> testdfr <-
>
data.frame(Date=seq(as.POSIXct("2008-08-01"),as.POSIXct("2008-09-01"),
> length=10))
> testdfr$yvar <- rnorm(10)
> sp <- interpSpline(yvar ~ Date, testdfr)
>
> preddfr <- data.frame(Date=as.POSIXct("2008-08-02"))
> predict(sp, preddfr)
>
>
> thanks,
> Remko
>
>
> -------------------------------------------------
> Remko Duursma
> Post-Doctoral Fellow
>
> Centre for Plant and Food Science
> University of Western Sydney
> Hawkesbury Campus
> Richmond NSW 2753
>
> Dept of Biological Science
> Macquarie University
> North Ryde NSW 2109
> Australia
>
> Mobile: +61 (0)422 096908
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
Thanks for that... the error message threw me off. r ------------------------------------------------- Remko Duursma Post-Doctoral Fellow Centre for Plant and Food Science University of Western Sydney Hawkesbury Campus Richmond NSW 2753 Dept of Biological Science Macquarie University North Ryde NSW 2109 Australia Mobile: +61 (0)422 096908 On Thu, Feb 26, 2009 at 2:07 PM, David Winsemius <dwinsemius at comcast.net> wrote:> It certainly appears that you just _did_ use it as such. You got a spline. > The only error thrown was from predict() and I think that was because you > needed to use a bit of extra coercion. > >> predict(sp, x=as.numeric(as.POSIXct("2008-08-02"))) > $x > [1] 1217649600 > > $y > [1] -0.4748701 > > attr(,"class") > [1] "xyVector" > > -- > David Winsemius > > On Feb 25, 2009, at 9:30 PM, Remko Duursma wrote: > >> Dear R-helpers, >> >> can I use a POSIXct date as the x variable in interpSpline? The help >> page says x and y need to be numeric... is there a workaround? >> >> example: >> >> library(splines) >> testdfr <- >> data.frame(Date=seq(as.POSIXct("2008-08-01"),as.POSIXct("2008-09-01"), >> length=10)) >> testdfr$yvar <- rnorm(10) >> sp <- interpSpline(yvar ~ Date, testdfr) >> >> preddfr <- data.frame(Date=as.POSIXct("2008-08-02")) >> predict(sp, preddfr) >> >> >> thanks, >> Remko >> >> >> ------------------------------------------------- >> Remko Duursma >> Post-Doctoral Fellow >> >> Centre for Plant and Food Science >> University of Western Sydney >> Hawkesbury Campus >> Richmond NSW 2753 >> >> Dept of Biological Science >> Macquarie University >> North Ryde NSW 2109 >> Australia >> >> Mobile: +61 (0)422 096908 >> >> ______________________________________________ >> R-help at r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > >