why suppress Error in Rmarkdown doesn't work? - r

Question

I want to supress Errors in Rmw files. So, i've tried to set the global chunk option error=TRUE, but it doesn't work. Also it doesn't work to set the chunk option error=TRUE directly in the chunk.
Here is an example code:
\begin{document}
\SweaveOpts{concordance=TRUE}
abc
<<setup, cache=F, include=F>>=
library(knitr)
library(formatR)
opts_chunk$set(error=TRUE)
knit_hooks$set(error=TRUE)
#
<<a,error=TRUE>>=
A <- 5
# of course, that doesnt work, but i want the error message as chunk output
A * B
#
\end{document}
I don't understand why it doesn't work
Only the error message:
"Error in eval(expr, .GlobalEnv) : object 'L' not found"
appears.

Answer 1

You seem to be using Sweave from base R rather than knitr. If you were using knitr, you'd get a warning about the \SweaveOpts{concordance=TRUE} statement.
If you are using RStudio, this is one of the Project Options. If you are running things directly, run knitr::knit("<your filename>"), instead of Sweave("<your filename>").
There are a couple of other errors that will stop knitr from working; this version fixes them:
\documentclass{article}
\begin{document}
abc
<<setup, cache=F, include=F>>=
library(knitr)
library(formatR)
opts_chunk$set(error=TRUE)
#
<<a,error=TRUE>>=
A <- 5
# of course, that doesnt work, but i want the error message as chunk output
A * B
#
\end{document}
The changes were:
You need the \documentclass line at the start.
You don't want the \SweaveOpts{concordance=TRUE} statement.
You don't want the knit_hooks$set(error=TRUE) statement.