[R] R: R scripts and parameters

Prof Brian Ripley ripley at stats.ox.ac.uk
Thu Feb 19 10:04:51 CET 2009


You seem not to have put the R bin directory in your path.  That is 
where Rterm, Rscript ... are installed (and the installer does not 
change the PATH for you).

On Thu, 19 Feb 2009, mauede at alice.it wrote:

> Sorry. This is still unclear to me.
> I generated a file called "Test.R" that contains the following lines:
>
> commandArgs(TRUE)
> cat("\n A = ",A,"\n")
> cat("\n B = ",B,"\n")
> cat("\n C = ",C,"\n")
>
> First of all I have to clarify which command line we are talking about.
> If I run the command "Rscript" from a Windows terminal, the system does not recognize such a command:
> C:\Documents and Settings\Monville\Utilities-Dir>Rscript Test.R aa bb cc
> "Rscript" non ? riconosciuto come comando interno o esterno,
> un programma eseguibile o un file batch.
> The above system response tells me that Rscript is not recognized either as an internal or external command, an executable or a batch file.
>
> In fact Rscript is an R command. Nevertheless, I started an R session and tried such a command from R console command line
> and got the following:
>> getwd()
> [1] "C:/Documents and Settings/Monville/Utilities-Dir"
>> Rscript Test.R aa bb cc
> Error: unexpected symbol in "Rscript Test.R"
>
> I feel I do not have a good grasp of how to run R scripts the same way as I usually run C programs.
> Any help is welcome.
> Thank  you.
>
> Maura
>
>
>
>
>
> -----Messaggio originale-----
> Da: Duncan Murdoch [mailto:murdoch at stats.uwo.ca]
> Inviato: mar 17/02/2009 17.34
> A: mauede at alice.it
> Cc: r-help at stat.math.ethz.ch
> Oggetto: Re: [R] R scripts and parameters
>
> On 2/17/2009 10:55 AM, mauede at alice.it wrote:
>> A couple of weeks ago I asked how it is possible to run an R script (not a function) passing some parameters.
>> Someone suggested the function "commandArgs()".
>> I read the on-line help and found no clarifying example. Therefore I do not know how to use it appropriately.
>> I noticed this function returns the pathname of the R executable which is not what I need.
>>
>> I meant to ask if it is possible to open an R session and launch a script passing parameters that the script can retrieve and use itself.
>> Just like in C I can run a program and call it with  some arguments
>>
>>> Example_Prog A B C
>>
>> The program "Example_Prog" can acess its own arguments through the data structures "argc" an "argv".
>>
>> How can I launch an R script simulating the above mechanism ?
>> Shall I use source ("script-name") ?
>> Where are the arguments to be passed, as part of the source call ?
>> Is the function "commandArgs" to be places as one of the first code lines of the script in order to access its own arguments ?
>> Is there any "commandArgs" usage example ?
>
>
> Gabor gave you a solution from within R.  If you want to run a script
> from the command line, then use commandArgs(TRUE).  For example, put
> this into the file test.R:
>
> commandArgs(TRUE)
>
> (The TRUE says you only want to see the trailing arguments, not
> everything else on the command line.)
>
> Then from the command line, do
>
> Rscript test.R A B C
>
> and you'll see the output
>
> [1] "A" "B" "C"
>
> Duncan Murdoch
>
>
>
>
> tutti i telefonini TIM!
>
>
> 	[[alternative HTML version deleted]]
>
>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595




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