Thanks for your suggestion, I solved the problem using:

#+headers: :results output latex
#+begin_src R :session *R* :exports results
...
print(xtable(summary(mypca)))
#+end_src

Regards
Riccardo




2012/2/14 Andreas Leha <andreas.leha@med.uni-goettingen.de>
Christophe Pouzat <christophe.pouzat@gmail.com> writes:

> Sorry,
>
> Checking foo.org
> (http://orgmode.org/w/?p=worg.git;a=blob_plain;f=org-contrib/babel/examples/foo.org;hb=HEAD)
> I got the correct way to do it:
>
> #+begin_src R :results output latex :exports results
>   library(xtable)
>   xtable(foo, caption = "ANOVA Table", label = "tab:one",
>       digits = c(0, 0, 2, 0, 2, 3, 3))
> #+end_src
>
> Does it solve your problem?
>
> Christophe
>
> Riccardo Romoli <ric.romoli@gmail.com> writes:
>
>> If I set :export latex when I exports to LaTeX I have only the R code, not the
>> table.
>>
>> Best
>>
>> 2012/2/14 Christophe Pouzat <christophe.pouzat@gmail.com>
>>
>>     Riccardo Romoli <ric.romoli@gmail.com> writes:
>>
>>     > Hi, I work with org-babel and R.
>>     > In the R session I create a table that I have to export to LaTeX.
>>     > This is the code I use:
>>     >
>>     > #+headers: :results latex
>>     > #+begin_src R :session *R* :exports results
>>     > .....
>>     >   print(xtable(summary(mypca)))
>>     > #+end_src
>>     >
>>     > I do not understand why the exported table is delimited by "|":
>>     >
>>     > |% latex table generated in R 2.14.1 by xtable 1.6-0 package |
>>     > | % Tue Feb 14 16:21:48 2012 |
>>     > | \begin{table}[ht] |
>>     >   | \begin{center} |
>>     >     | \begin{tabular}{rrrrrrrrrrrrrrrrr} |
>>     >       | \hline |
>>     >       | & PC1 & PC2 & PC3 & PC4 & PC5 & PC6 & PC7 & PC8 & PC9 & PC10 &
>>     >       PC11 & PC12 & PC13 & PC14 & PC15 & PC16 \\ |
>>     >       | \hline |
>>     >       | Standard deviation & 3.4693 & 2.8113 & 2.5561 & 2.2668 &
>>     >       2.0015 & 1.9236 & 1.7287 & 1.6220 & 1.4288 & 1.3456 & 1.2596 &
>>     >       1.2195 & 1.1278 & 1.0778 & 0.8390 & 0.0000 \\ |
>>     >       | Proportion of Variance & 0.2188 & 0.1437 & 0.1188 & 0.0934 &
>>     >       0.0728 & 0.0673 & 0.0543 & 0.0478 & 0.0371 & 0.0329 & 0.0289 &
>>     >       0.0270 & 0.0231 & 0.0211 & 0.0128 & 0.0000 \\ |
>>     >       | Cumulative Proportion & 0.2188 & 0.3625 & 0.4813 & 0.5747 &
>>     >       0.6476 & 0.7149 & 0.7692 & 0.8170 & 0.8541 & 0.8871 & 0.9159 &
>>     >       0.9429 & 0.9661 & 0.9872 & 1.0000 & 1.0000 \\ |
>>     >       | \hline |
>>     >       | \end{tabular} |
>>     >     | \end{center} |
>>     >   | \end{table} |
>>     > | |
>>     >
>>     > Should I change some headers settings??
>>     >
>>     > Best
>>     >
>>
>>     Hi Riccardo,
>>
>>     Try ":exports latex" instead of ":exports results"
>>
>>     Christophe
>>     --
>>
>>     Most people are not natural-born statisticians. Left to our own
>>     devices we are not very good at picking out patterns from a sea of
>>     noisy data. To put it another way, we are all too good at picking out
>>     non-existent patterns that happen to suit our purposes.
>>     Bradley Efron & Robert Tibshirani (1993) An Introduction to the Bootstrap
>>
>>     --
>>
>>     Christophe Pouzat
>>     MAP5 - Mathématiques Appliquées à Paris 5
>>     CNRS UMR 8145
>>     45, rue des Saints-Pères
>>     75006 PARIS
>>     France
>>
>>     tel: +33142863828
>>     mobile: +33662941034
>>     web: http://www.biomedicale.univ-paris5.fr/physcerv/C_Pouzat.html
>>
>>

Hi Riccardo,

additionally, if you do not want to get too tightly bound to LaTeX, check
out the ascii-package, e.g.

#+begin_src R :results output org wrap :exports results
 library(ascii)

 ## from the lm help page:
 ctl <- c(4.17,5.58,5.18,6.11,4.50,4.61,5.17,4.53,5.33,5.14)
 trt <- c(4.81,4.17,4.41,3.59,5.87,3.83,6.03,4.89,4.32,4.69)
 group <- gl(2,10,20, labels=c("Ctl","Trt"))
 weight <- c(ctl, trt)
 lm.D9 <- lm(weight ~ group)
 lm.D90 <- lm(weight ~ group - 1) # omitting intercept

 print(ascii(anova(lm.D9)), type="org")
#+end_src


Cheers,
Andreas