[R] permutation of rows of a matrix

[John Fox]

Dear Manuel,

Although ?sample doesn't specifically describe permuting the rows of a
matrix, it does say that "sample(x) generates a random permutation of the
elements of x (or 1:x)." Indexing the rows of the matrix by a permutation of
1:x (where x is the number of rows) doesn't seem to be much of a leap.

Regards,
 John

--------------------------------
John Fox
Department of Sociology
McMaster University
Hamilton, Ontario
Canada L8S 4M4
905-525-9140x23604
http://socserv.mcmaster.ca/jfox 
-------------------------------- 

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Manuel 
> López-Ibáñez
> Sent: Saturday, April 15, 2006 9:44 AM
> To: r-help at stat.math.ethz.ch
> Subject: Re: [R] permutation of rows of a matrix
> 
> help(sample) does not say anything about randomly permuting 
> the rows of a matrix M by using M[sample(m,m),]. Perhaps it 
> could be added as an example of use.
> 
> John Fox wrote:
> > Dear Jose,
> > 
> > M[sample(m, m),] will randomly permute the rows of M. [You probably 
> > could have figured this out via help.search("permutation"), which 
> > would have led you to sample().]
> > 
> > Regards,
> >  John
> > 
> > --------------------------------
> > John Fox
> > Department of Sociology
> > McMaster University
> > Hamilton, Ontario
> > Canada L8S 4M4
> > 905-525-9140x23604
> > http://socserv.mcmaster.ca/jfox
> > --------------------------------
> > 
> > 
> >>-----Original Message-----
> >>From: r-help-bounces at stat.math.ethz.ch 
> >>[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of javargas
> >>Sent: Saturday, April 15, 2006 7:53 AM
> >>To: r-help at stat.math.ethz.ch
> >>Subject: [R] permutation of rows of a matrix
> >>
> >>How can I generate a random permutation between rows of a 
> matrix M (of 
> >>m rows and n columns)?
> >>
> >>Thanks for your help,
> >>
> >>Jose
> >>
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> > 
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