[R] plotting to stdout

[Gene Selkov]

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)

--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.
>
>