[R] losing row.names in matrix operations

[Gabor Grothendieck]

If its regular you can convert it to ts or zoo.
If its irregular convert it to zoo.  There is no
reason to expect rollapply to work with objects
of other classes.  Read ?ts and ?zoo.  In
ts note the start and frequency arguments.


On Sat, Aug 2, 2008 at 7:50 AM, rcoder <mpdotbook at gmail.com> wrote:
>
> Hi everyone,
>
> I have a data frame, with the following format:
>
> MatDate->
>        row.names       ID1     ID2     ID3
> 1       date1
> 2       date1
> 3       date3
>        etc
>
> but I cannot perform a rollapply() statement on the matrix without
> converting the matrix into a time series.
> i.e. MatTs<-ts(MatDate)

Use the start and frequency arguments. See ?ts

>
> Only then will my rollapply statement work:
> MatMin<-rollapply(MatTs, 2,by=2, min, na.rm=F)
>
> If I apply the rollapply() statement to the dataframe, I get the following
> error: Error: could not find function "rollapply"
>
> The problem is that when I convert the data.frame matrix into a time series
> matrix, I lose the dates in the row.names column. I just want to know if
> anyone could suggest a way to get around this problem, i.e. keep the
> row.names column in place, and use the rollapply() statement as above.
>
> Thanks,
>
> rcoder
> --
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