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 <dwinsem...@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@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.
>
>
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