[R] Declaring variables in R

[Thomas Lumley]

On Thu, 18 Oct 2007, Moshe Olshansky wrote:

> Please forgive me if my question is answered in Help
> FAQ no. 23481739...

If it were, we might well not forgive you -- the faq isn't *that* long. But it isn't.

> In VBA one can use a special statement (Option
> Explicit) which does not allow using variables which
> have not been previously declared. As far as I
> remember this can also be done in Matlab (or at least
> there is a utility which can check whether your
> program uses undeclared variables).
>
> My question is: does such an option/utility exist in
> R?
>

The codetools package provides a tool that scans your code for undeclared variables.  It is not perfect --- it has occasional false positives and false negatives -- but it is pretty good.

      -thomas

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle