The gtools package also includes a function, 'running', which accomplishes
the desired task:
> library(gtools)
> t(running(1:5, width=3, fun=c))
[,1] [,2] [,3]
1:3 1 2 3
2:4 2 3 4
3:5 3 4 5
>
On 11/30/06 8:56 PM, "Marc Schwartz" <[EMAIL PROTECTED]> wrote:
> Here is another possibility, though I may be missing how the Matlab
> function handles incomplete rows generated at the end of the source
> vector. I have not fully tested this, so it may yet require some
> tweaking and certainly appropriate error checking.
>
> I am presuming that the basic premise is that each row is of length
> 'window' and that it overlaps with the END of prior row by 'overlap'.
>
>
> Buffer <- function(x, window, overlap)
> {
> Res <- NULL
>
> while (length(x) >= window)
> {
> Res <- c(Res, x[1:window])
> x <- x[(1 + window - overlap):length(x)]
> }
>
> matrix(Res, ncol = window, byrow = TRUE)
> }
>
>
>> Buffer(1:5, 3, 2)
> [,1] [,2] [,3]
> [1,] 1 2 3
> [2,] 2 3 4
> [3,] 3 4 5
>
>> Buffer(1:10, 4, 2)
> [,1] [,2] [,3] [,4]
> [1,] 1 2 3 4
> [2,] 3 4 5 6
> [3,] 5 6 7 8
> [4,] 7 8 9 10
>
> HTH,
>
> Marc Schwartz
>
>
> On Thu, 2006-11-30 at 16:32 -0800, Charles C. Berry wrote:
>> See
>>
>> ?embed
>>
>> It is not quite the same, but this seems to be what you want - at least
>> for the example you give:
>>
>>> t( embed(1:5,3) )[3:1,]
>> [,1] [,2] [,3]
>> [1,] 1 2 3
>> [2,] 2 3 4
>> [3,] 3 4 5
>>>
>>
>> On Fri, 1 Dec 2006, Martin Ivanov wrote:
>>
>>> Hello! I am new to R. I could not find a function analogous to matlab's
>>> function buffer, which is used in signal processing. Is there such a
>>> function in R? What I need to do is as follows. If I apply the function
>>> to the vector c(1:5) for example with a window length 3 and overlapping
>>> 2, I need to get a matrix like this:
>>> 1 2 3
>>> 2 3 4
>>> 3 4 5
>>> In matlab this is achieved with the function buffer. Is there ananalogous R
>>> function?
>
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