Hi all,

  I have a series of measurements made over different types of road surfaces
and capacity that I want to summarize in tables via LaTeX.  Ideally I'd like
a table similar to this (
http://www.andy-roberts.net/misc/latex/tutorial4/multirow.png ) with mean/SD
of the measurement broken down by road type (both surface and capacity).
Ideally it would be extensible so that when I add layers of heirarchy on top
the complexity does not increase exponentially (e.g. measurement by road
surface/capacity by month by neighborhood), but rather take those additional
levels as arguments.

xtable() is a wonderful thing, but it seems to lack a method for displaying
the results broken down by a factor as in the table above.  One can easily
write code to add lines between the segments, but then the levels are
repeated for each row.  Has anyone written a method for xtable() to handle
this (assuming not, otherwise it'd be in the package)?  Is there any way to
pass a \multirow call to xtable() (assuming not, otherwise it'd be in the
documentation)?

If the answers to both of the above are "no," then can someone give me a
pointer to a basic but thorough explanation of how generic functions and
methods are structured (S3, I believe), preferably online.  I tried doing
this via getS3method("xtable","data.frame") and working from there, but the
method merely sets up things for the generic function to render (it's likely
I'm getting my terminology somewhat wrong here; please forgive) and what I
want to do is beyond the bounds of modifying it in this way.  I've looked
through _Writing R Extensions_, but the Generic Functions and Methods
chapter is only about a page long.

Thanks on behalf of all the lurkers.  I've learned much just by reading the
daily digests over the last few weeks.
Ari

Ari Friedman
abfriedman@gmail.com

	[[alternative HTML version deleted]]

