[R] write data from function into external table

[Gabor Grothendieck]

If functions don't modify their environment then its generally
easier to debug programs so it encourarges better programming.

On 6/14/06, Sebastian Leuzinger <Sebastian.Leuzinger at unibas.ch> wrote:
> Thanks for the hints, they are useful to me. However, I still do not
> understand why my approach fails. In a user defined function, R does not seem
> to want to write into an object defined outside this function. (see my first
> example below). I guess there is some logic behind this.
>
> On Wednesday 14 June 2006 14:22, you wrote:
> > Here are two alternatives.  See ?"<<-"
> >
> > testfct1 <- function() test[1] <<- 100
> >
> > # following one can be written more compactly as
> > #   testfct2 <- function(test) replace(test, 1, 100)
> > testfct2 <- function(test) { test[1] <- 100; test }
> >
> > # test
> > test <- 1:3; testfct1(); test
> > test <- 1:3; test <- testfct2(test); test
> >
> > On 6/14/06, Sebastian Leuzinger <Sebastian.Leuzinger at unibas.ch> wrote:
> > > Dear list,
> > > My apologies if a solution / explanation to this already exists on the
> > > list, but it is difficult to assign it to a certain keyword.
> > >
> > > test<-c(1:3)
> > > testfct <- function(x) {test[1]<-100}
> > >  test
> > > [1] 1 2 3
> > >  testfct(1)
> > > [1] 1 2 3
> > >
> > > Basically, I would like to write data into an external table that the
> > > function does not know. Why is this not working / what alternatives
> > > exist?
> > >
> > > Thanks, Sebastian
> > >
> > > ------------------------------------------------
> > > Sebastian Leuzinger
> > > University of Basel, Department of Environmental Science
> > > Institute of Botany
> > > Schönbeinstr. 6 CH-4056 Basel
> > > ph    0041 (0) 61 2673511
> > > fax   0041 (0) 61 2673504
> > > email Sebastian.Leuzinger at unibas.ch
> > > web   http://pages.unibas.ch/botschoen/leuzinger
> > >
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>
> --
> ------------------------------------------------
> Sebastian Leuzinger
> University of Basel, Department of Environmental Science
> Institute of Botany
> Schönbeinstr. 6 CH-4056 Basel
> ph    0041 (0) 61 2673511
> fax   0041 (0) 61 2673504
> email Sebastian.Leuzinger at unibas.ch
> web   http://pages.unibas.ch/botschoen/leuzinger
>