Question

I am running R v2.14.1 on Ubuntu. I am writing a script that will generate a data frame, which represents a table of results.

I would like to output this ‘table’ as a .tex file so that I can create an ‘academic publication’ quality table, for printing. I have heard of Sweave (and read some overview docs about Sweave) – so I think this is the way to proceeed. However having said that I have not actually seen an example where Sweave outputs a dataframe as a tex file – all of the Sweave examples I have seen so far, seem contrived and not something that I can build upon.

Are there some guidelines I can follow, to output tex from a dataframe? Also, will it be simpler (more straight forward), if I built the TeX string directly from my R script and saved the string to file? (It is not clear to me, what Sweave offers over and above manually building the TeX string ‘manually’).

Answer 1

The xtable package has some examples of how to generate tables – see vignette. When you’re writing a chunk, make sure you set the chunk to <<results=tex>>. See Sweave example, for instance, this.

This is how I would output a data.frame.

<<results=tex>>
    xtable(my.data.frame)
@

And the raw result would looks something like this:

> xtable(my.data.frame)
% latex table generated in R 2.14.1 by xtable 1.6-0 package
% Tue Feb 14 10:03:03 2012
\begin{table}[ht]
\begin{center}
\begin{tabular}{rllr}
  \hline
 & p & q & r \\ 
  \hline
1 & condition\_a & grp\_1 &   3 \\ 
  2 & condition\_a & grp\_1 &   3 \\ 
  3 & condition\_a & grp\_1 &   4 \\ 
  4 & condition\_a & grp\_1 &   1 \\ 
  5 & condition\_b & grp\_1 &   4 \\ 
  6 & condition\_b & grp\_1 &   3 \\ 
  7 & condition\_b & grp\_1 &   5 \\ 
  8 & condition\_b & grp\_1 &   5 \\ 
  9 & condition\_a & grp\_2 &   4 \\ 
  10 & condition\_a & grp\_2 &   1 \\ 
  11 & condition\_a & grp\_2 &   1 \\ 
  12 & condition\_a & grp\_2 &   1 \\ 
  13 & condition\_b & grp\_2 &   5 \\ 
  14 & condition\_b & grp\_2 &   1 \\ 
  15 & condition\_b & grp\_2 &   5 \\ 
  16 & condition\_b & grp\_2 &   2 \\ 
   \hline
\end{tabular}
\end{center}
\end{table}