[R] Hmisc's latex: na.blank and grouping not working as expected

[Marius Hofert]

Dear expeRts,

Why does na.blank=TRUE not replace the NA's in the following LaTeX table?

x <- matrix(1:72, ncol=4, nrow=8)
colnames(x) <- c("gr1.sgr1", "gr1.sgr2", "gr2.sgr1", "gr2.sgr2")
rn <- apply(expand.grid(beta=c(0.25, 0.75), n=c(100, 500), d=c(10, 100))[, 3:1], 2, rmNames)
x <- cbind(rn, x) # append columns containing the row labels
x[2,5] <- NA
stopifnot(is.na(x[2,5]))

require(Hmisc)
latex(x,
      file="",
      na.blank=TRUE,
      rowlabel=c("d", "n", "beta"),
      booktabs=TRUE)

In the end, I would like to have the columns displayed in groups like this:

                        Group 1                     Group 2
d   n   beta   Sub-group 1   Sub-group 2   Sub-group 1   Sub-group 2
10  100 0.25       1             9
        0.75       2
    500 0.25       3            10
        0.75       4            11             ...           ...
100 100 0.25       5            12
        0.75       6            13
    500 0.25       7            ...
        0.75       8

If anybody knows how to do this, please let me know :-) This is (one of) my trial(s):

latex(x,
      file="",
      cgroup=c("", "Group 1", "Group 2"),
      n.cgroup=c(3, 2, 2),
      na.blank=TRUE,
      rowlabel=c("d", "n", "beta"),
      booktabs=TRUE)

Why are there two empty columns inserted and the table has suddenly 9 columns instead of 7?

Cheers,

Marius