Stopwatch function in R

Question

Is there an R timer or stopwatch function similar to MATLAB\'s tic/toc?

Answer 1

Just for completeness: you can actually 'simulate' tic and toc in R, so that you can write

tic
## do something
toc

without parentheses. The trick is to abuse the print function, as demonstrated in Fun: tic and toc in R:

tic <- 1
class(tic) <- "tic"

toc <- 1
class(toc) <- "toc"

print.tic <- function(x, ...) {
    if (!exists("proc.time"))
        stop("cannot measure time")
    gc(FALSE)
    assign(".temp.tictime", proc.time(), envir = .GlobalEnv)
}

print.toc <- function(x,...) {
    if (!exists(".temp.tictime", envir = .GlobalEnv))
        stop("did you tic?")
    time <- get(".temp.tictime", envir = .GlobalEnv)
    rm(".temp.tictime", envir = .GlobalEnv)
    print(res <- structure(proc.time() - time,
                           class = "proc_time"), ...)
    invisible(res)
}

So typing

tic
Sys.sleep(2)
toc

should results in something like this:

   user  system elapsed 
  0.000   0.000   2.002 

As I said, it's a trick; system.time, Rprof and packages such as rbenchmark are the way to measure computing time in R.