Just showing an example to represent my seemingly simple problem.
i generate a variable with random TRUE/FALSE.
<<>>=
data <- sample(c(TRUE, FALSE), size = 1, replace = TRUE)
@
Somewhere in the TeX (knitr), i need to print whether its TRUE or FALSE.
\Sexpr{!is.na(data)}
but my text output is blank. I am not sure whats the problem?