Command-line arguments: Difference between revisions

Line 1,012:

Following adapted from [http://quantitative-ecology.blogspot.com/2007/08/including-arguments-in-r-cmd-batch-mode.html this post by Forester]:

Suppose you want to call your script <tt>test.r</tt> with the arguments <tt>a=1 b=c(2,5,6)</tt>, where <tt>b</tt> is a numeric vector. Suppose you also want to redirect your output to <tt>test.out</tt> (not that you have a choice: I still don't know how to make R send shell-script output to stdout). You would then run

Suppose you want to call your script <tt>test.r</tt> with the arguments <tt>a=1 b=c(2,5,6)</tt>, where <tt>b</tt> is a numeric vector. Suppose you also want to redirect your output to <tt>test.out</tt> (not that you have a choice--I still don't know how to make R send shell-script output to stdout). You would then run

<lang R>R CMD BATCH --vanilla '--args a=1 b=c(2,5,6)' test.r test.out &</lang>

<lang R>R CMD BATCH --vanilla --slave '--args a=1 b=c(2,5,6)' test.r test.out</lang>

from the commandline. Your resulting output <tt>test.out</tt> would contain (e.g., if you <tt>cat</tt> it)

⚫

<pre>[1] 2

<pre>R version 2.14.0 (2011-10-31) [or whatever version you are running,

followed by several more lines of R startup cruft,

before it echoes your code:]

> ## Read the commandline arguments

> args <- (commandArgs(TRUE))

>

> ## args is now a list of character vectors

> ## First check to see if arguments are passed.

> ## Then cycle through each element of the list and evaluate the expressions.

> if (length(args)==0) {

+ print("No arguments supplied.")

+ # supply default values

+ a = 1

+ b = c(1,1,1)

+ } else {

+ for (i in 1:length(args)) {

+ eval(parse(text=args[[i]]))

+ }

> print(a*2)

⚫

[1] 2

> print(b*3)

[1] 6 15 18

>

> proc.time()

user system elapsed

0.168 0.026 0.178

</pre>

If you know how to get the output

* sent to stdout (i.e., as is normal with shell scripts)

* done without the profiling

please update this example!

=={{header|RapidQ}}==