selecting ith rows of a matrix
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 f?r Genomorientierte Bioinformatik Technische Universit?t M?nchen Wissenschaftszentrum Weihenstephan 85350 Freising, Germany http://mips.gsf.de/staff/pagel