Re: [R] flatten a matrix and unflatten it

From: Gabor Grothendieck <ggrothendieck_at_myway.com>
Date: Tue 22 Mar 2005 - 10:23:24 EST

Bill Simpson <William.Simpson <at> drdc-rddc.gc.ca> writes:

:
: I want to flatten a matrix and unflatten it again. Please tell me how to
: do it.
:
: 1. given a matrix:
: x1 y1 z1
: x2 y2 z2
: ...
: xk yk zk
: convert it to a vector:
: x1, y1, z1, x2, y2, z2, ..., xk, yk, zk
:
: 2. given a vector:
: x1, y1, z1, x2, y2, z2, ..., xk, yk, zk
: convert it to a matrix
: x1 y1 z1
: x2 y2 z2
: ...
: xk yk zk
:
: It is known that the number of dimensions is 3.
:

myvector <- c(t(mymatrix))
mymatrix <- matrix(myvector, byrow = TRUE, nc=3)

If column-wise is ok rather than row-wise as you show, then omit t() in the first line and byrow = TRUE in the second.



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue Mar 22 10:33:28 2005

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:30:52 EST