If you specifically want to know which packages were loaded by the script
then using a vanilla version of R (i.e. one where only base packages are
loaded):
vanilla_search <- search()
source("myRprg.R")
setdiff(search(), vanilla_search)
On Wed, Jun 20, 2018 at 4:08 AM, Sigbert Klinke
... or if the argument is just quoted text or a numeric value as in your
library() example, don't parse the text and use regex's to search for the
function call and pick out the text of the arguments.
Again, this only works (I think) for the simple sort of case of your
example. Beyond that,
You need to recursively walk the parse tree/AST. See, e.g.,
https://adv-r.hadley.nz/expressions.html#ast-funs
Hadley
On Wed, Jun 20, 2018 at 10:08 AM, Sigbert Klinke
wrote:
> Hi,
>
> I have read an R program with
>
> expr <- parse("myRprg.R")
>
> How can I extract the parameters of a specifc R
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