>>>>> Duncan Murdoch writes: > The help for cbind() and rbind() says > "For cbind (rbind), vectors of zero length (including NULL) are ignored > unless the result would have zero rows (columns), for S compatibility. > (Zero-extent matrices do not occur in S3 and are not ignored in R.)"
> This leads to an inconsistency. > M <- matrix(NA, 0, 0) # Make a 0x0 matrix > N <- matrix(NA, 0, 1) # Make a 0x1 matrix > dim(rbind(M, NULL, NULL)) # adds 2 rows to M > #> [1] 2 0 > dim(rbind(N, NULL, NULL)) # leaves N unchanged > #> [1] 0 1 > You get an extra row on the 0x0 matrix for each NULL value that is bound > to it, but the 0xn matrix is unchanged for n > 0. > Clearly from the help this is intentional, but is it desirable? > Wouldn't it make more sense for NULL to be ignored by rbind() and > cbind()? I would agree :-) Best -k > Duncan Murdoch > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
