Handling Latex backslashes in xtable

Question

I have a table that includes the following column:

 mytable <- data.frame(beta_0 = c(1,2,3)

What I want to do is output a table with a column header in latex markup, e.g. $\beta_0$

However, I can not seem to figure out how to output the "$\beta_0$" using print.xtable:

colnames(mytable) <- "$\beta_0$"
library(xtable)
print(xtable(mytable), include.rownames = F)

returns a column header of

\eta\_0\$

instead of

$\beta_0$

I presume that the answer is the "sanitize.colnames.function" argument to print.xtable, but it is not obvious to me how to use this, and ?print.xtable provides no examples.

Specifically, I would like to output a latex table like:

\begin{table}[ht]
 \begin{center}
  \begin{tabular}{r}
    \hline
    $\beta_0$ \\ 
    \hline
    1.00 \\ 
    2.00 \\ 
    3.00 \\ 
    \hline
  \end{tabular}
 \end{center}
\end{table}

Answer 1

Two issues here; first, you need a double backslash as otherwise it treats it as a control sequence. Second, by default, xtable sanitizes text so that it won't break LaTeX. Use one of the sanitize. parameters to control this; to do no sanitizing, pass it the identity function.

colnames(mytable) <- "$\\beta_0$"
print(xtable(mytable), include.rownames = F, sanitize.colnames.function = identity)

Answer 2

this is what did the trick for me:

mat <- round(matrix(c(0.9, 0.89, 200, 0.045, 2.0), c(1, 5)), 4)
rownames(mat) <- "$y_{t-1}$"
colnames(mat) <- c("$R^2$", "$\\bar{x}$", "F-stat", "S.E.E", "DW")
mat <- xtable(mat)
print(mat, sanitize.text.function = function(x){x})

This way you avoid the backslash issue in the table text.