Printing repetetively on the same line in R

Question

I was just wondering what is the best way in R to keep on printing on the same line in a loop, to avoid swamping your console? Let's say to print a value indicating your progress, as in

for (i in 1:10) {print(i)}

Edit:

I tried inserting carriage returns before each value as in

for (i in 1:10000) {cat("\r",i)}

but that also doesn't quite work as it will just update the value on the screen after the loop, just returning 10000 in this case.... Any thoughts?

NB this is not to make a progress bar, as I know there are various features for that, but just to be able to print some info during the progression of some loop without swamping the console

Answer 1

You have the answer, it's just looping too quickly for you to see. Try:

for (i in 1:10) {Sys.sleep(1); cat("\r",i)}

EDIT: Actually, this is very close to @Simon O'Hanlon's answer, but given the confusion in the comments and the fact that it isn't exactly the same, I'll leave it here.

Answer 2

Try using cat()...

for (i in 1:10) {cat(paste(i," "))}
#1  2  3  4  5  6  7  8  9  10  

cat() performs much less conversion than print() (from the horses mouth).

To repeatedly print in the same place, you need to clear the console. I am not aware of another way to do this, but thanks to this great answer this works (in RStudio on Windows at least):

for (i in 1:1e3) {
  cat( i )
  Sys.sleep(0.01)
  cat("\014")
}