[R] Console display "buffer size"

[Peter Ehlers]

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.

Peter Ehlers

>
> With thanks,
> Ted.
>
> -------------------------------------------------
> E-Mail: (Ted Harding) <Ted.Harding at wlandres.net>
> Date: 01-Apr-2013  Time: 21:37:17
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