R - Handling cut intervals of form [x,y] in tables when converting to LaTeX

Question

I'm working on a document in R, with knitr to pdflatex and am using the extended version of toLatex from memisc.

When I'm producing a table with cut intervals however, the square brackets are not sanitised and the pdflatex job errors because of the existence of [.

I tried putting sanitize=TRUE in the knitr chunk code, but this only works for tikz.

Previously, I have used gsub and replaced the string in the R object itself which is rather inelegant. I'm hoping someone could point me in the direction of a nuance of memisc or knitr that I'm missing or another function/method that would easily handle latex special characters.

Example

library("memisc")
library("Hmisc")
example<-data.frame(cbind(x=1:100,y=1:100))
example$x<-cut2(example$x,m=20)
toLatex(example)

UPDATE

Searching SO I found a post about applying latexTranslate with apply function, but this requires characters so I would have to unclass from factor to character.

I found another SO post that identifies the knitr:::escape_latex function however, the chunk then outputs the stuff as markup instead of translating it (using results='asis') or produces an R style table inside a code block (using results='markup'). I tried configuring it as a hook function in my parent document and it had the effect of outputting all the document contents as markup. This is a brand new area for me so I probably implemented it incorrectly.

<<setup,include=FALSE>>=
hook_inline = knit_hooks$get('inline')
knit_hooks$set(inline = function(x) {
  if (is.character(x)) x = knitr:::escape_latex(x)
  hook_inline(x)
})
@
...
<<tab-example,echo=FALSE,cache=TRUE,results='asis',sanitize=TRUE,inline=TRUE>>=
library("Hmisc")
library("memisc")
    example<-data.frame(cbind(x=1:100,y=1:100))
    example$x<-cut2(example$x,m=20)
    toLatex(example)
@

According to @yihui this is the wrong way to go

UPDATE 2

I have created a gsub wrapper which will escape percentages etc, however the [ symbol still pushes latex into maths mode and errors.

Answer 1

Courtesy of folks on the tex SE, a [ directly after a line break(\\) is considered an entry into math-mode. It is very simple to prevent this behaviour by adding {} into the output just before a [. My function looks like:

escapedLatex<-function (df = NULL) 
{
    require("memisc")
    gsub(gsub(x = toLatex(df, show.xvar = TRUE), pattern = "%", 
        replacement = "\\%", fixed = TRUE), pattern = "[", replacement = "{}[", 
        fixed = TRUE)
}

I'd be very happy to see any alternative, more elegant solutions around and will leave it open for a few days.