[R] plotting to stdout

[Duncan Murdoch]

On 9/7/2007 2:15 PM, Gene Selkov wrote:
> Thanks a ton, Duncan!
> 
> So I have verified that this line works:
> 
>    echo "postscript(file=\"\", command=\"cat\"); plot(0)" | r --vanilla --slave
> 
> Wonderful! (albeit a little unobvious)

I would include an explicit "dev.off()" after the plotting; I'm not sure 
all devices guarantee a clean shutdown when R quits.

Duncan Murdoch
> 
> --Gene
> 
> On Fri, 7 Sep 2007, Duncan Murdoch wrote:
> 
>> On 9/7/2007 12:36 PM, Gene Selkov wrote:
>>> I have found two prior instances of this question in R-help, but I can't 
>>> find the answer, and I'm giving up on mindless tinkering.
>>> 
>>>    http://tolstoy.newcastle.edu.au/R/help/03a/5994.html
>>>    https://stat.ethz.ch/pipermail/r-help/2004-December/062259.html
>>> 
>>> I must be able to pipe the poltting commands to stdin and receive the plot 
>>> on stdout, with errors written to stderr, should any occur.
>>> 
>>> Here's what I tried:
>>> 
>>> file test.r:
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> postscript(stdout())
>>> plot(0)
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> 
>>> This command:
>>> 
>>>     cat test.r | r --vanilla --slave
>>> 
>>> writes the output to a file named "1"
>>> 
>>> I have also tried:
>>> 
>>>    postscript(file=stdout())
>>>    postscript(file=file("stdout"))
>>> 
>>> In the latter case, the output goes to the file named "3".
>>> 
>>> Other graphics devices do the same thing.
>>> 
>>> It is interesting that write.table() supports the file=stdout() idiom. If 
>>> there is no official option to do this, I will appreciate a hint about the 
>>> spot in the code where I can fix it.
>>
>> The ?postscript man page suggests that
>>
>> postscript(file="", command="cat")
>>
>> should do what you want (or maybe something other than "cat" for the 
>> passthrough).  The file arg is described as a character string, not a 
>> connection, so I wouldn't expect stdout() to work.  For write.table(), the 
>> arg is defined to be either the name of a file or an open connection.
>>
>> Duncan Murdoch
>>
>>> 
>>> Thanks,
>>> 
>>> --Gene
>>> 
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>> sessionInfo()
>>> R version 2.5.1 (2007-06-27)
>>> i386-apple-darwin8.10.1
>>> 
>>> locale:
>>> C
>>> 
>>> attached base packages:
>>> [1] "stats"     "graphics"  "grDevices" "utils"     "datasets"  "methods"
>>> [7] "base"
>>> 
>>> ______________________________________________
>>> R-help at stat.math.ethz.ch mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide 
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.