On Wed, Oct 27, 2010 at 10:07 AM, Ivan Calandra <ivan.calan...@uni-hamburg.de> wrote: > > > Le 10/27/2010 15:45, Gabor Grothendieck a écrit : >> >> On Wed, Oct 27, 2010 at 8:38 AM, Ivan Calandra >> <ivan.calan...@uni-hamburg.de> wrote: >>> >>> What I don't understand is why vectors (with more than one value) don't >>> have >>> dimensions. They look like they do have 1 dimension. For me no dimension >>> would be a scalar. Like in geometry: a point has no dimension, a line has >>> 1, >>> a square has 2, a cube 3 and so on. Is it because of some internal >>> process? >>> The intuitive geometry way of thinking is not programmatically relevant? >>> >> Maybe you used APL before. The basic structure in that language is >> an array but that is not the case for R. The basic structure for data >> is a vector and more complex data objects are build from that. An >> array is a more complex object than a vector. A 1d array is not the >> same as a vector. Dimensions are an additional concept unlike APL. > > I've never used any other language before. It's just that I compare the > printing of an object to a geometric object, which means that a vector of > length > 1 has 1 dimension. In my mind, as I said, a point has no dimension, > a line has 1, a square has 2, a cube 3 and so on. But now, I kind of > understand that in R, dimensions do not really correspond to the "shape" of > an object, it's just an attribute. I'll then just accept that 1d array are > not vectors and that vectors have NULL dimension (which is not zero I > guess!)
It would be preferable to say that dimension is not a concept associated with vectors at all. Saying it is but its NULL makes it seem like its still there. -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com ______________________________________________ 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.