Re: [R] zooreg and window

From: Katrina Bennett <kebennett_at_alaska.edu>
Date: Thu, 14 Apr 2011 12:34:16 -0800

Hi Achim,

Yes, this worked. I added the two strings

regts.start <- as.Date(regts.start)
regts.end <- as.Date(regts.end)

and changed the frequency to 1 in my zooreg call.

The window call now works perfectly.

I'm still wrapping my head around POSIXct and ISOdatetime and how they need to be applied appropriately!

Thank you,

Katrina

On Thu, Apr 14, 2011 at 12:26 AM, Achim Zeileis <Achim.Zeileis_at_uibk.ac.at> wrote:
> On Wed, 13 Apr 2011, Katrina Bennett wrote:
>
>> Hello, I have a following time series data
>>
>> head(mend.dat)
>>
>> ID PARAM Year Month Day Value SYM
>> 1 15052500     1 1965     5  15   128   A
>> 2 15052500     1 1965     5  16   135   A
>> 3 15052500     1 1965     5  17   157   A
>> 4 15052500     1 1965     5  18   176   A
>> 5 15052500     1 1965     5  19   198   A
>> 6 15052500     1 1965     5  20   241   A
>>
>>
>> I have loaded these data into as a zooreg object. The entire time
>> series runs from 1965-05-15 until 2010-12-31.
>>
>> I have generated dates using ISOdatetime.
>>
>> regts.start <- ISOdatetime(year.start, mo.start, day.start, hour=0,
>> min=0, sec=0, tz="GMT")
>> regts.end <- ISOdatetime(year.end, mo.end, day.end, hour=0, min=0,
>> sec=0, tz="GMT")
>
> Here, you use "POSIXct" for your time index, below in the window() call you
> use "Date". The latter is more appropriate here because you appear to have
> daily data (and not intraday data).
>
> Thus, you can do
>
> regts.start <- as.Date(regts.start)
>
> or create it from scratch via
>
> regts.start <- as.Date("1965-05-15")
>
> and analogously for regts.end.
>
> The deltat in the zooreg() call is then simply 1.
>
>> Then, I generate a zoo time series from the data.
>>
>> zts <- zooreg(mend.dat$Value, start = regts.start, end = regts.end,
>> frequency = 1, deltat = 86400)
>>
>> I now want to subset using window.
>>
>> window(zts, start=as.Date("2000-01-01"), end=as.Date("2000-01-02"))
>>
>> This results in the following error message.
>>
>>
>> Data:
>> factor(0)
>> 1496 Levels:  100 1000 10000 101 1010 10100 102 1020 103 1030 104 1040
>> 105 1050 10500 106 1060 107 1070 108 1080 ... Eqp
>>
>> Index:
>> character(0)
>> Warning messages:
>> 1: In which(in.index & all.indexes >= start & all.indexes <= end) :
>>  Incompatible methods ("Ops.POSIXt", "Ops.Date") for ">="
>> 2: In which(in.index & all.indexes >= start & all.indexes <= end) :
>>  Incompatible methods ("Ops.POSIXt", "Ops.Date") for "<="
>>
>>
>> Why is this happening?
>>
>> Thanks for your help.
>>
>> Katrina Bennett
>>
>> ______________________________________________
>> 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.
>>
>

-- 
Katrina E. Bennett
PhD Student
University of Alaska Fairbanks
International Arctic Research Center
930 Koyukuk Drive, PO Box 757340
Fairbanks, Alaska 99775-7340
907-474-1939 office
907-385-7657 cell
kebennett_at_alaska.edu


Personal Address:
UAF, PO Box 752525
Fairbanks, Alaska 99775-2525
bennett.katrina_at_gmail.com

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Received on Thu 14 Apr 2011 - 21:39:13 GMT

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