Hi Katia, On Wed, Jun 29, 2011 at 12:50 PM, Katia Smirnova <katiasm...@gmail.com> wrote: > Hi, I have a 4D data file from MATLAB, call it X, that I want to analyze in > R. The first 3 dimensions are x y z coordinates and the forth is a value in > time. > > If you took a sample vector in matlab it would look like > > vec1 = X(x1, y1, z1, :) > vec2 = X( x2, y2, z2, :) > > this would give you all values (I have 300 of them) corresponding to this > (x1,y1,z1) point of X. > > Now I read the MATLAB datafile 4D X into R and want to address vec1 and vec2 > in R and work with the fourth column values only.
How did you import the MATLAB file? > I tried something like X[ x1, y1, z1, ] to pull out the 4th column values > but R tells me that X has incorrect dimensions. We need a description of X. dim(X) and str(X) might be good starts. You don't really provide enough information to be able to answer. Sarah -- Sarah Goslee http://www.functionaldiversity.org ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.