[R] Console display "buffer size"

Peter Ehlers ehlers at ucalgary.ca
Tue Apr 2 00:42:50 CEST 2013

On 2013-04-01 15:06, Ted Harding wrote:
> On 01-Apr-2013 21:26:07 Robert Baer wrote:
>> On 4/1/2013 4:08 PM, Peter Ehlers wrote:
>>> On 2013-04-01 13:37, Ted Harding wrote:
>>>> Greetings All.
>>>> This is a somewhat generic query (I'm really asking on behalf
>>>> of a friend who uses R on Windows, whereas I'm on Linux, but
>>>> the same phenomenon appears on both).
>>>> Say one has a largish dataframe -- call it "G" -- which in the
>>>> case under discussion has 592 rows and 41 columns. The intention
>>>> is to display the data by simply entering its name (G) as command.
>>>> Say the display console has been set wide enough to display 15
>>>> columns (determined by lengths of column names). Then R will output
>>>> succesively to the console, in continuous flow:
>>>>     Chunk 1: rows 1:592 of columns 1:15
>>>>     Chunk 2: rows 1:592 of columns 16:30
>>>>     Chunk 3: rows 1:592 of columns 31:41
>>>> If the number of rows that can be displayed on the screen is, say, 60,
>>>> then only rows 533:592 of Chunk 3 will be visible in the first instance.
>>>> However, on my Linux system at any rate, I can use Shift+PgUp to
>>>> scroll back up through what has been output to the console. It seems
>>>> that my friend proceeds similarly.
>>>> But now, after a certain number of (Shift+PgUps), one runs out
>>>> of road before getting to Row 1 of Chunk 1 (in my friend's case,
>>>> only Rows 468-592 of Chunk 1 can be seen).
>>>> The explanation which occurs to me is that the console has a "buffer"
>>>> in which such an output is stored, and if the dataframe is too big
>>>> then lines 1:N (for some N) of the output are dropped from the start
>>>> of the buffer, and it is impossible to go further back than line (N+1)
>>>> of Chunk 1 where in this case N=467 (of course one may not even be
>>>> able to go further back than Chunk K, for some K > 1, for a bigger
>>>> dataframe).
>>>> The query I have is: In the light of the above, is there a way to
>>>> change the size of the "buffer" so that one can scroll all the way
>>>> back to the very first row of Chunk 1? (The size-change may perhaps
>>>> have to be determined empirically).
>>> Isn't this set by the 'bufbytes' and 'buflines' specifications in the
>>> Rconsole file?
>>> Anyway, it's probably best to use 'View' to inspect data.
>> Although I have not tried them, Windows RGUI  [ -- Edit | GUI
>> Preferences --] has settings for both buffer and lines which on my
>> 64-bit machine default to 250000 and 8000 respectively.
>> Rob Baer
>>> Peter Ehlers
> Thanks for the replies, Rob and Peter. Rob's reply in particular
> corresponds to what my friend has himself just found out in his
> Windows installation of R. It seems, however, that this setting
> is once-and-for-all in an R session (I can't check that myself).
> Re Peter's comment: I don;t seem to have an "Rconsole" file
> anywhere in my Linux installation. Is it unique to Windows?

Yes, I believe Rconsole is Windows only. But let me re-iterate my
advice: use View() to inspect a data.frame. When I need to do a
fair bit of this and find that typing "View" is too much effort,
I save a couple of keystrokes by redefining .V <- View. The nice
thing is that you can scroll both horizontally and vertically
and you can even do it sans mouse (arrow/page keys).

Peter Ehlers

> Once again, thanks. Very helpful.
> Ted.
> -------------------------------------------------
> E-Mail: (Ted Harding) <Ted.Harding at wlandres.net>
> Date: 01-Apr-2013  Time: 23:06:21
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