copying huge strings via clipboard? - R-help

Fri, Mar 4, 2022 8:45 AM #

Hi,
This is on Windows10 via the R gui  .  I, admittedly inadvisably, tried 
to create a new character object by first copying a 1-million character 
string (including lead and trail "'" chars) to the clipboard and then, 
in the console,

 >> foo <-
and hitting "paste"

What I found is that, around 5000 characters, a newline ( "\n") char 
showed up.  Is this something that the Windows Clipboard does, or 
something odd about pasting into a command in R?

Postscript:  using

 >>  bar <- readChar('thefile.txt',1e6)

the import works perfectly.

Carl Witthoft
personal: carl at witthoft.com
The Witthoft Group, Consulting
https://witthoftgroup.weebly.com/

David Winsemius

Fri, Mar 4, 2022 9:34 AM #

On 3/4/22 08:45, Carl Witthoft wrote:

I'm the wrong person to comment on Windows clipboard features.

ISTR that there is a character limit for R command line input, at least 
in some or perhaps all R installations.

Subject: 	[R] parsing -?input?buffer overflow 
<http://markmail.org/message/iyjlmfsb4kp63cyi> 	permalink 
<http://markmail.org/message/iyjlmfsb4kp63cyi>
From: 	Prof Brian Ripley (rip... at stats.ox.ac.uk)
Date: 	Jun 13, 2008 1:52:06 am
List: 	org.r-project.r-help

"R does have limits on the command line length (1024 bytes up to 
R-devel, 4096 bytes there). What happens if you exceed that depends on 
the interface you are using (and you have not told us). Beyond that, the 
parser has a limit of MAXELTSIZE (8192 bytes) on strings.

I don't see any need for 'improvement' though: why are you entering very 
long strings as part of the R program? They are data, and e.g. 
readLines() and scan() have no limits on string length beyond those 
imposed by R's internals (2^31-1 bytes)."

I think that info is still current since a search of the 
../manuals/R-int page says:

--- copied

The|R_StringBuffer|structure needs to be initialized, for example by

static R_StringBuffer ex_buff = {NULL, 0, MAXELTSIZE};

which uses a default size of|MAXELTSIZE = 8192|bytes.Most current uses 
have a static|R_StringBuffer|structure, which allows the (default-sized) 
buffer to be shared between calls to e.g.|grep|and even between 
functions: this will need to be changed if R ever allows concurrent 
evaluation threads.

--- end copy

David


>
> Postscript:? using
>
> >>? bar <- readChar('thefile.txt',1e6)
>
> the import works perfectly.
>
>

Jeff Newmiller

Fri, Mar 4, 2022 12:13 PM #

Windows can handle up to 2GB in the clipboard... but IMO it isn't a good practice to rely on. Use files for reproducibility and portability. It is common for command line shells of all varieties to limit their buffer sizes considerably.

On March 4, 2022 9:34:15 AM PST, David Winsemius <dwinsemius at comcast.net> wrote:

On 3/4/22 08:45, Carl Witthoft wrote:

Hi,
This is on Windows10 via the R gui? .? I, admittedly inadvisably, 
tried to create a new character object by first copying a 1-million 
character string (including lead and trail "'" chars) to the clipboard 
and then, in the console,

foo <-

and hitting "paste"

What I found is that, around 5000 characters, a newline ( "\n") char 
showed up.? Is this something that the Windows Clipboard does, or 
something odd about pasting into a command in R?

I'm the wrong person to comment on Windows clipboard features.

ISTR that there is a character limit for R command line input, at least 
in some or perhaps all R installations.

Subject: 	[R] parsing -?input?buffer overflow 
<http://markmail.org/message/iyjlmfsb4kp63cyi> 	permalink 
<http://markmail.org/message/iyjlmfsb4kp63cyi>
From: 	Prof Brian Ripley (rip... at stats.ox.ac.uk)
Date: 	Jun 13, 2008 1:52:06 am
List: 	org.r-project.r-help

"R does have limits on the command line length (1024 bytes up to 
R-devel, 4096 bytes there). What happens if you exceed that depends on 
the interface you are using (and you have not told us). Beyond that, the 
parser has a limit of MAXELTSIZE (8192 bytes) on strings.

I don't see any need for 'improvement' though: why are you entering very 
long strings as part of the R program? They are data, and e.g. 
readLines() and scan() have no limits on string length beyond those 
imposed by R's internals (2^31-1 bytes)."

I think that info is still current since a search of the 
../manuals/R-int page says:

--- copied

The|R_StringBuffer|structure needs to be initialized, for example by

static R_StringBuffer ex_buff = {NULL, 0, MAXELTSIZE};

which uses a default size of|MAXELTSIZE = 8192|bytes.Most current uses 
have a static|R_StringBuffer|structure, which allows the (default-sized) 
buffer to be shared between calls to e.g.|grep|and even between 
functions: this will need to be changed if R ever allows concurrent 
evaluation threads.

--- end copy

Sent from my phone. Please excuse my brevity.