key-value mapping in C inside R?
On Dec 30, 2010, at 11:25 AM, Matteo Bertini wrote:
Il giorno 30/dic/2010, alle ore 16.03, Simon Urbanek ha scritto:
On Dec 30, 2010, at 7:50 AM, Matteo Bertini wrote:
I'm testing some modifications in arima.c. I've noticed that a big internal array of double (rbar) is usually sparse and I'd like to add an option to store it as key-value mapping. Is there a library function or some other approach already used inside the R core for key-value mappings?
environment created with hash=TRUE, e.g.: e = new.env(TRUE, emptyenv()) e[["foo"]] = "bar" You can even set "size" with the expected size if you know it in advance.
Interesting, but is it possible to use this from the C code?
Sure, assignment:
void defineVar(SEXP symbol, SEXP value, SEXP rho)
retrieval:
SEXP findVarInFrame(SEXP rho, SEXP symbol)
so the above assignment would be in C
defineVar(install("foo"), mkString("bar"), env)
where env is the environment created above.
Cheers,
Simon