[R] permutation/randomization

Philipp Pagel p.pagel at wzw.tum.de
Wed Apr 9 22:15:56 CEST 2008

On Wed, Apr 09, 2008 at 11:08:28AM -0700, Grant Gillis wrote:

> I would like to randomize data within columns.

I think the following line does what you want (minus preserving the row

apply(data, 2, sample)

Maybe someone smarter than me knows how to preserve the row names. I
would probably just steal them from the original data frame:

nam = row.names(data)
apply(data, 2, sample)
row.names(foo) = nam


Dr. Philipp Pagel                              Tel.  +49-8161-71 2131
Lehrstuhl für Genomorientierte Bioinformatik   Fax.  +49-8161-71 2186
Technische Universität München
Wissenschaftszentrum Weihenstephan
85350 Freising, Germany

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