[R] Extract function parameters from a R expression

[Hadley Wickham]

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
<sigbert using wiwi.hu-berlin.de> wrote:
> Hi,
>
> I have read an R program with
>
> expr <- parse("myRprg.R")
>
> How can I extract the parameters of a specifc R command, e.g. "library"?
>
> So, if myprg.R containes the lines
>
> library("xyz")
> library("abc")
>
> then I would like to get "xyz" and "abc" back from expr.
>
> Thanks in advance
>
> Sigbert
>
> --
> https://hu.berlin/sk
>
>
>
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