On Mar 27, 2012, at 12:03 PM, Terry Therneau wrote: > On 03/23/2012 10:58 AM, Simon Urbanek wrote: >> This is my shot at a cheat sheet. >> comments are welcome. >> >> Simon >> >> > I was looking through the cheat sheet. It's nice. There are a few things in > it that I can't find in the documentation though. Where would one find a > description? (I can guess, but that may be dangerous). > > mkNamed
It is a shorthand for using allocVector and then setting names (which can be tedious). It's a simple way to create a result list/object (a very common thing to do): SEXP res = PROTECT(mkNamed(VECSXP, (const char*[]) { "foo", "bar", ""})); // fill res with SET_VECTOR_ELT(res, ..) setAttrib(res, R_ClassSymbol, mkString("myClass")); UNPROTECT(1); return res; Note that the sentinel is "" (not not NULL as commonly used in other APIs). Also you don't specify the length because it is determined from the names. > R_Naint (I don't see quite how this differs from using NA_INTEGER to set a > result) It doesn't really -- NA_INTEGER is defined to be R_NaInt. In theory NA_INTEGER being a macro could be a constant instead -- maybe for efficiency -- but currently it's not. > R_PreserveObject, R_ReleaseObject (Advantages/disadvantages wrt PRESERVE?) > I guess you mean wrt PROTECT? Preserve/Release is used for objects that you want to be globally preserved - i.e. they will survive exit from the function. In contrast, the protection stack is popped when you exit the function (both by error or success). Cheers, Simon ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel