[R] recommended way to group function calls in Sweave

[Rainer Schuermann]

What I usually do when I have to write a report with some functions I use 
multiple times is that I put them in a separate file (call it "setup.Rnw" or 
so).

The first chunk there loads the libraries, sets initial variable values etc:

<<echo=FALSE, results=hide>>=
library(  xtable )
d <- iris
ind <- 1
@

Then I have a number of chunks that are not evaluated at this point:

<<chunk_name_1,eval=FALSE,echo=FALSE>>=
summary(d[ , ind])
cor(d[ , ind])
@

<<chunk_name_2,eval=FALSE,echo=FALSE>>=
# produce a nice table from some data
@

In my master file, I load these "definitions" first

SweaveInput( "setup.Rnw" )

and from here, I can suse the named chunks almost like function calls, as you 
you describe below. The advantage (for me) is that I have only one place where 
I maintain the functions code, and only one line in the "real document", 
rather than a lot of code, possibly distributed over the document..

Rgds,
Rainer




On Wednesday 25 April 2012 16:20:13 Liviu Andronic wrote:
> On Wed, Apr 25, 2012 at 3:41 PM, Duncan Murdoch
> <murdoch.duncan at gmail.com> wrote:
> > I would use the last method, or if the calls were truly repetitive (i.e.
> > always identical, not just the same pattern), use a named chunk.
> >
> Labeled chunks are indeed what I was looking for [1]. As far as I
> understand, this is what "Sweave functions" (or are these macros?)
> look like:
> 
> 
> <<>>=
> d <- iris
> ind <- 1:2
> @
> 
> <<sw>>=
>   summary(d[ , ind])
>   cor(d[ , ind])
> @
> 
> <<>>=
> d <- iris
> ind <- 2:4
> <<sw>>
> @
> 
> 
> Regards
> Liviu
> 
> [1] vignette('Sweave', 'utils')
> 
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