Handling Latex backslashes in xtable - r

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.