# Detect When the Random Number Generator Was Used

If you ever need to figure out if a function call in R generated a random number or not, here is a simple trick that you can use in an interactive R session. Add the following to your ~/.Rprofile(*): if (interactive()) { invisible(addTaskCallback(local({ last <- .GlobalEnv$.Random.seed function(...) { curr <- .GlobalEnv$.Random.seed if (!identical(curr, last)) { msg <- "TRACKER: .Random.seed changed" if (requireNamespace("crayon", quietly=TRUE)) msg <- crayon::blurred(msg) message(msg) last <<- curr } TRUE } }), name = "RNG tracker")) } It works by checking whether or not the state of the random number generator (RNG), that is, .

#### Henrik Bengtsson

MSc CS | PhD Math Stat | Associate Professor | R Foundation | R Consortium

Associate Professor