On Sun, Apr 20, 2008 at 08:16:11PM +0000, David Winsemius wrote:
Gabor Csardi <csardi at rmki.kfki.hu> wrote in
news:20080420133926.GA28167 at localdomain:
Hmm, my understanding is different,
m <- matrix(sample(10*10), ncol=10)
m2 <- rbind( m[1:5,], 1:10, m[6:10,] )
m3 <- cbind( m[,1:8], 1:10, m[,9:10] )
I read the question the same way and, in response to the part of
the question asking for no temporary matrix, offer this refinement
on your suggestion:
m <- rbind( m[1:5,], 1:10, m[6:10,] ) # row insertion or ...
# not to be followed by, but rather instead column insertion ..
m <- cbind( m[,1:8], 1:10, m[,9:10] )
There might be something wrong with my eyes, but where is the
refinement here? Your lines are literally the same as mines. There
is no temporary matrix here, m2 and m3 are the results, he wanted
either between row 5 and 6 _OR_ column 8 and 9.
Oh, if you mean that we immediately put back the result into 'm',
then 1) it does not really matter, R will create a temporary matrix
internally anyway,