R help - Jun 2010 - Generate a list of all subsequence of length k from an array

Hi, 
I would like to generate a list of all subsequence of length k from an  array
with length n (k < n). The result should be organized in a matrix.
So the matrix should look like the following whereas each row is one of a
subsequence of len k.

[a[1:k],
 a[2:(k+1)]
 a[3:(k+2)]
 ...
 a[(n-k+1):n]

Is there away to do this with sapply method?

thanks,
Ron
 		 	   		  
_________________________________________________________________
The New Busy is not the too busy. Combine all your e-mail accounts with Hotmail.

ID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_4
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On Jun 22, 2010, at 2:35 AM, Ron Shefi wrote:
>
> Hi,
> I would like to generate a list of all subsequence of length k from  
> an  array with length n (k < n). The result should be organized in a  
> matrix.
> So the matrix should look like the following whereas each row is one  
> of a subsequence of len k.
>
> [a[1:k],
> a[2:(k+1)]
> a[3:(k+2)]
> ...
> a[(:n]
>
> Is there away to do this with sapply method?
I suppose you could try (untested in absence of example):

sapply(1:(n-k+1), function(x) { a[x:(x+k)] })

-- 

David Winsemius, MD
West Hartford, CT

You could try this:

embed(a, k)

On Tue, Jun 22, 2010 at 3:35 AM, Ron Shefi <ron380@hotmail.com> wrote:
>
> Hi,
> I would like to generate a list of all subsequence of length k from an
>  array with length n (k < n). The result should be organized in a
matrix.
> So the matrix should look like the following whereas each row is one of a
> subsequence of len k.
>
> [a[1:k],
>  a[2:(k+1)]
>  a[3:(k+2)]
>  ...
>  a[(n-k+1):n]
>
> Is there away to do this with sapply method?
>
> thanks,
> Ron
>
> _________________________________________________________________
> The New Busy is not the too busy. Combine all your e-mail accounts with
> Hotmail.
>
> ID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_4
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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