[R] selecting ith rows of a matrix

[Philipp Pagel]

On Wed, Apr 29, 2009 at 01:58:06PM +0530, Umesh Srinivasan wrote:
> Hi all,
> 
> If  I have a huge matrix/ dataframe and I want to create a new matrix/
> dataframe with every second (or third, or fourth etc.) row of the original
> matrix, how can I do it? Any help much appreciated.

Others ahve already poitned out soltions using seq9(). I'd just like
to add an alternative approach making use of R's logical indexing and 
recycling rules:

mat <- matrix(1:1000, 100, 5)
mat2 <- mat[c(T,F),]

cu
	Philipp

-- 
Dr. Philipp Pagel
Lehrstuhl für Genomorientierte Bioinformatik
Technische Universität München
Wissenschaftszentrum Weihenstephan
85350 Freising, Germany
http://mips.gsf.de/staff/pagel