[R] shifting data in matrix by n rows

[Gabor Grothendieck]

Actually my last reply will drop one row since its pushed off
to beyond the data range.  You can avoid that with zooreg:

# from before for comparison
lag(z, -1, na.pad = TRUE)

# pure shift - note use of zooreg here
# Unlike lag.zoo, lag.zooreg can shift beyond data range
zr <- as.zooreg(z)
lag(zr, -1)

# lag.zooreg does not have an na.pad= arg but we
# can merge it with original times to get NA row.
merge(lag(zr, -1), zoo(, time(zr)))

On Thu, Jul 10, 2008 at 5:52 PM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> See ?lag and in zoo ?lag.zoo.  Both pages have
> examples. Using lag.zoo here it is with your data:
>
> Lines <- "Date   Apples   Oranges   Pears
> 1/7     2          3            5
> 2/7     1          4            7
> 3/7     3          8            10
> 4/7     5          7            2
> 5/7     6          3            5"
>
> library(zoo)
>
> # z <- read.zoo("myfile.dat", header = TRUE, format = "%d/%m")
> z <- read.zoo(textConnection(Lines), header = TRUE, format = "%d/%m")
>
> lag(z, -1, na.pad = TRUE)
>
> On Thu, Jul 10, 2008 at 3:12 PM, rcoder <michael.larsson at gmail.com> wrote:
>>
>> Hi everyone,
>>
>> Thanks very much for all your replies.
>>
>> I'm interested in hearing more about the lag function. I remember coming
>> across this in the R intro manual, but I couldn't figure out how to apply it
>> to my case. Does anyone know how it is applied, assuming a time series data
>> frame?
>>
>> Thanks,
>>
>> rcoder
>>
>>
>>
>> Gabor Grothendieck wrote:
>>>
>>> If its a zoo or ts time series you can use the lag function.
>>>
>>> On Wed, Jul 9, 2008 at 2:57 PM, rcoder <michael.larsson at gmail.com> wrote:
>>>>
>>>> Hi everyone,
>>>>
>>>> I have some data in a matrix, and I want to shift it down by one row. The
>>>> matrix in question has a date column. Does anyone know of a way to shift
>>>> the
>>>> data by one row, whilst preserving the date column in the matrix - i.e.
>>>> shift the data and leave the date column in the current location?
>>>>
>>>> Thanks,
>>>>
>>>> rcoder
>>>> --
>>>> View this message in context:
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>>>> Sent from the R help mailing list archive at Nabble.com.
>>>>
>>>> ______________________________________________
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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/shifting-data-in-matrix-by-n-rows-tp18368420p18389841.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.
>>
>