I am using knitr for a report wherein I have a lot of inline output text, mostly numeric values, using \Sexpr{}. I want to highlight All these inline outputs in my generated pdf.
Example code:
\documentclass[12pt]{article}
\begin{document}
<<echo=FALSE, include=FALSE>>=
N <- 100 # Total
N_f <- 60 # Women
@
There were \Sexpr{N} people in the company, \Sexpr{N_f} women and \Sexpr{N - N_f} men.
\end{document}
Hence, in the output all the number should be highlighted, i.e. with a shaded background (similar to using with \hl{} with the \usepackage{soul}).
It seems to me that the solution would use one of the inline output hooks. Another possibility might be to write a LaTeX function which search all the \Sexpr{...} expressions in the entire document and highlights them in the generated pdf. I am still learning and can not figure out how to implement these.
Thanks for any help or hints.
Note: The knitr page by yihui talks about manipulation of the numeric value (scientific notation, digits after decimal points) which I have got covered.
The output hook inline can be used to style output from \Sexpr{}. This is as simple as
knit_hooks$set(inline = function(x) { sprintf("\\textbf{%s}", x)})
Just define an arbitrary function that takes an argument x and returns the string to be printed. In this example I used \textbf to make the output bold, but this can be extended to any LaTeX commands.
In this answer, Yihui suggests an improvement that still takes the default inline hook into account. This ensures rounding as usually performed by the default hook:
hook_inline <- knit_hooks$get('inline')
knit_hooks$set(inline = function(x) { sprintf("\\textbf{%s}", hook_inline(x))})