xtable() to preserve latex function in R

Question

I'm producing a series of tables in R that will include fractions once I report them in latex. To do this, I'm using the paste() function to apply the fraction command in r, however when I xtable it, it loses the "\f" in the beginning. Below is code. Do you know how to preserve the full function? Thanks

x <- as.vector(rbind(1, paste("\frac{",1, "}{", 2, "}", sep ="" ))) 
y <- as.vector(rbind(2, paste("\frac{", 2, "}{", 3, "}", sep ="" )))    
table<- cbind(x,y)
xtable(table)

Answer 1

Two things are needed; first, double the backslash, and second, turn off the usual text sanitizing function by passing identity (which just returns the input).

> x <- as.vector(rbind(1, paste("\\frac{",1, "}{", 2, "}", sep ="" ))) 
> y <- as.vector(rbind(2, paste("\\frac{",2, "}{", 3, "}", sep ="" )))    
> print(xtable(cbind(x,y)), sanitize.text.function=identity)
% latex table generated in R 3.0.1 by xtable 1.7-1 package
% Wed Jul  3 10:17:21 2013
\begin{table}[ht]
\centering
\begin{tabular}{rll}
  \hline
 & x & y \\ 
  \hline
1 & 1 & 2 \\ 
  2 & \frac{1}{2} & \frac{2}{3} \\ 
   \hline
\end{tabular}
\end{table}