Hello, About the Range() function, I think it should handle decreasing ranges too... But, idk if using Matlabs approach or R approach:
R's: a <- 1 b <- 10 print(a:b) 1 2 3 4 5 6 7 8 9 10 print(b:a) 10 9 8 7 6 5 4 3 2 1 Matlab's a = 1; b = 10; disp(a:b); 1 2 3 4 5 6 7 8 9 10 disp(b:a); numeric(0) disp(b:-1:a) 10 9 8 7 6 5 4 3 2 1 I think that we are in the R domain, so we should use Range(b, a) normally (my humble opinion). About Casting, this is a good example: Rcout << Range(0, 10) << std::endl; This does not compute... What should I do? Rcout << as<IntegerVector>(Range(0, 10)) << std::endl; or Rcout << (IntegerVector)(Range(0, 10)) << std::endl; -- Francisco Bischoff, MD, MSc Faculty of Medicine of the University of Porto, Portugal - Master of Medical Informatics | topic: time series - Research Associate | artificial intelligence for health <https://mailtrack.io/trace/link/261f22c687548623a329c468d9ee8e2177eb0450?url=http%3A%2F%2Fcintesis.eu%2Fai4health%2F&userId=3785237&signature=3e0be0b7841b95c4> @ cintesis.eu <https://mailtrack.io/trace/link/37900be19872e834994af798ab1d53480613e66c?url=http%3A%2F%2Fcintesis.eu&userId=3785237&signature=91ac56f3d356e8bd> - Teaching Assistant | department of community medicine, information and health decision sciences @ med.up.pt <https://mailtrack.io/trace/link/6951087469cd0e54d4bc365eedae9d9ad24d5970?url=http%3A%2F%2Fmed.up.pt&userId=3785237&signature=ac6fffd4ce8944ca> ORCID: 0000-0002-5301-8672 | Mendeley: francisco-bischoff | Google: tCeA0uUAAAAJ | ResearcherID: H-8261-2016 | ResearchGate: Francisco_Bischoff | CiênciaID B413-E0A0-DE8D | LinkedIn: franzbischoff On Wed, Jan 6, 2021 at 6:11 AM Dirk Eddelbuettel <e...@debian.org> wrote: > > Francisco, > > On 5 January 2021 at 13:58, Francisco Bischoff wrote: > | First of all, let me thank all involved with the Rcpp package! > | > | I just have a (maybe silly) question, but I struggle with this frequently > | in my codes: > | > | Range() vs IntegerVector > | > | One example is when I need a reverse index, like R's 10:1, so I had to > | write my own function that returns an IntegerVector. But, to work I have > to > | do this ugly code: > | > | IntegerVector dot_rev_idxs1 = ::seq((i - 1), beginidx); > | IntegerVector dot_rev_idxs2 = ::seq((idx_nn - 1), (beginidx + > | idx_diff)); > | IntegerVector dot_rev_idxs3 = ::seq((i - 1 + window_size), ( > | beginidx + window_size)); > | IntegerVector dot_rev_idxs4 = ::seq((idx_nn - 1 + > window_size), ( > | beginidx + idx_diff + window_size)); > | dotproduct[dot_rev_idxs1] = > (NumericVector)((NumericVector)cumsum( > | data[dot_rev_idxs1] * data[dot_rev_idxs2] - > | > | data[dot_rev_idxs3] * data[dot_rev_idxs4]) + > | dotproduct[i]); > | > | I frequently have to cast the results with (NumericVector)... > | > | This also happens using Range(). But there is a difference if I use > Range() > | this way: my_vector[Range(0,10)]; or Range range = Range(0, > | 10); my_vector[range]; > | > | How is the proper way to deal with it? > > I am not sure I fully understand what it is that you try to and what you > are > struggling with. > > Could you construct a small self-contained example? > > | Other question: as<NumericVector() doesn't 'cast' right? Does it try to > | 'convert' formats? > | > | And finally, I see that Matlab has a unique way to deal with ranges: > | > | Ex.: > | > | 1) (1:10) --> 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 > | 2) (10:1) --> returns a vector with size zero > | 3) (10:-1:1) --> 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 > | > | Range() shouldn't at least reproduce the R's counterpart and accept > Range(10,1) > | == 10:1? > > We could probably generalize seq() to count down from 'high' to 'low'. Pull > requests welcome... > > Dirk > > -- > https://dirk.eddelbuettel.com > <https://mailtrack.io/trace/link/3dc4aa6120269dd41ea957abba6a53feaf80a120?url=https%3A%2F%2Fdirk.eddelbuettel.com&userId=3785237&signature=a0cad3f7fa0cc627> > | @eddelbuettel | e...@debian.org >
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