[R] Grouping commands so that variablas are removed automatically - like functions

[Rainer M Krug]

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Hi

I would like to group commands, so that after a group of commands has
been executed, the variables defined in that group are automatically
deleted.

My reasoning: I have a longer sript which is used to load data, do
analysis and plot graphs, all part of a document (in org-mode /
emacs).

I have several datasets which are loaded, and each one is quite
big. So after doing one part of the job (e.g. analysing the data and
storing the results) I want to delete all variables used to free space
and to avoid having these variables being used in the next block and
still having the old (for this block invalid) values.

I can't use rm(list=ls()) as I have some variables as "constants"
which do not change over the whole document and also some functions
defined.

I could put each block in a function and then call the function and
delete it afterwards, but this is as I see it abusing functions.

I don't want to keep track manually of the variables.

Therefore my question:

Can I do something like:

x <- 15

{ #here begins the block
a <- 1:100
b <- 4:400
} # here ends the block

# here are and b not defined anymore
# but x is still defined

{} is great for grouping the commands, but the variables are not
deleted afterwards.

Am I missing a language feature in R?

Rainer

- -- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
Biology, UCT), Dipl. Phys. (Germany)

Centre of Excellence for Invasion Biology
Stellenbosch University
South Africa

Tel :       +33 - (0)9 53 10 27 44
Cell:       +33 - (0)6 85 62 59 98
Fax :       +33 - (0)9 58 10 27 44

Fax (D):    +49 - (0)3 21 21 25 22 44

email:      Rainer at krugs.de

Skype:      RMkrug
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