[R] Clear last x entries of R console

Duncan Murdoch murdoch.duncan at gmail.com
Fri Feb 3 16:15:05 CET 2012


On 12-02-03 9:00 AM, angliski_jigit wrote:
> Hi All,
>
> I am trying to build in a progress-tracker into my loops that let me have a
> sense of their progress. I'd like to be able to output to screen a series of
> periods "...." etc. for each completion of the loop, but I<don't>  want to
> build a pyramid, e.g.
> .
> ..
> ...
> ....
> etc. So I need to be able to delete<the last line>  of the console entry to
> accomplish this. There are commands to erase the whole console, but that's
> not what I want either; ideally, the command would allow me to erase the
> last line or the last x lines.
>

Just don't write out a newline.  E.g.

for (i in 1:10) {
   cat(".")
   flush.console()
   Sys.sleep(1)
}

You can write out a CR using \r if you want to overwrite the previous 
line, e.g.

for (i in 10:0) {
   cat(i, " \r")
   flush.console()
   Sys.sleep(1)
}


Duncan Murdoch



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