[R] R scripts and parameters
murdoch at stats.uwo.ca
Tue Feb 17 17:34:15 CET 2009
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:
(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
 "A" "B" "C"
More information about the R-help