[R] losing row.names in matrix operations

[Gabor Grothendieck]

Constructing a zoo object is well covered in ?zoo
and in the three vignettes:

vignette("zoo")
vignette("zoo-quickref")
vignette("zoo-faq")


On Sat, Aug 2, 2008 at 10:27 AM, rcoder <mpdotbook at gmail.com> wrote:
>
> Thanks for your reply Gabor.
>
> As I already have a dates column in my dataframe (in column row.names), is
> it possible to preserve this whilst still making a data set suitable for
> rollapply()?
>
> Thanks,
>
> rcoder
>
>
>
> Gabor Grothendieck wrote:
>>
>> 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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>>>
>>> ______________________________________________
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>>>
>>
>> ______________________________________________
>> 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.
>>
>>
>
> --
> View this message in context: http://www.nabble.com/losing-row.names-in-matrix-operations-tp18788509p18789688.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> 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.
>