Prof Brian Ripley wrote: > This is nothing to do with the C API: isVector and isMatrix are not > part of the API (see Writing R Extensions for what it is). That's the > `issue' here. > > On Tue, 25 Oct 2005, Dominick Samperi wrote: > >> Consider the R code: >> mat <- matrix(seq(1,20),4,5) >> is.matrix(mat) # gives TRUE >> is.vector(mat) # gives FALSE >> >> On the other hand, if mat is passed through the .Call interface the >> corresponding SEXP (call it smat) satisfies >> isMatrix(smat) // TRUE >> isVector(smat) // TRUE >> >> Consequently, you cannot distinguish matrices from vectors. Looking >> at the dim attribute of a vector doesn't help because this is garbage. > > You can look to see if it has a dim attribute ... you could also look > at the C code for is.vector. The first option here does not seem to work. The code
SEXP dimAttr = getAttrib(smat, R_DimSymbol) does not set dimAttr to 0 (NULL) wheh smat is actually a vector. ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
