Francisco, Based on the opening post, I’d probably push you more toward Armadillo as Dirk was in the previous message. Using linspace<>(), may be a drop-in replacement for seq() with the appropriate helper functions. Long ago (~4+ years now) I wrote a few, see:
https://github.com/coatless/r-to-armadillo/blob/master/src/seq.cpp That said, Range is definitely preferred inside of subsets operations into Rcpp-like data structures. However, the subset and assign operation is a bit problematic with template expansion. So, the given example needs to have an intermediary: // Initialization: Rcpp::NumericVector my_vec = Rcpp::NumericVector::create(1, 2, 3, 4, 5, 6); // Subset and Assign to 5: Rcpp::IntegerVector subset_idx = Rcpp::Range(0, 3); my_vec[subset_idx] = 20; // Subset Positions: Rcpp::NumericVector subset_result = my_vec[Rcpp::Range(4, 5)]; Hope it helps. Best, JJB From: Rcpp-devel <rcpp-devel-boun...@lists.r-forge.r-project.org> on behalf of Francisco Bischoff <fbisch...@med.up.pt> Date: Friday, January 15, 2021 at 8:05 PM To: Dirk Eddelbuettel <e...@debian.org> Cc: "rcpp-devel@lists.r-forge.r-project.org" <rcpp-devel@lists.r-forge.r-project.org> Subject: Re: [Rcpp-devel] Ranges and Casting Thanks for the tips. Still, Range() is the correct way to write: NumericVector my_vec(200); my_vec(Range(0,10)) = 10; ? Thanks in advance -- 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://urldefense.com/v3/__https:/mailtrack.io/trace/link/1765b288bbce44d233e851a8d862ec594378aa04?url=http*3A*2F*2Fcintesis.eu*2Fai4health*2F&userId=3785237&signature=1b62d7a180130981__;JSUlJSU!!DZ3fjg!oa0yWHu4WaDeqycuBEcPRuw3vEvJrYARPPIAzJNsnxdet6loFCJ7O95nLR4ByfJyNzg$> @ cintesis.eu<https://urldefense.com/v3/__https:/mailtrack.io/trace/link/89b15c4212d5d6c8d4ba354ec92ab002ba9a96ef?url=http*3A*2F*2Fcintesis.eu&userId=3785237&signature=5fa97b31373fa664__;JSUl!!DZ3fjg!oa0yWHu4WaDeqycuBEcPRuw3vEvJrYARPPIAzJNsnxdet6loFCJ7O95nLR4B0QFIUzg$> - Teaching Assistant | department of community medicine, information and health decision sciences @ med.up.pt<https://urldefense.com/v3/__https:/mailtrack.io/trace/link/32f5f446b7bc0d597241524764b3636b5a75d466?url=http*3A*2F*2Fmed.up.pt&userId=3785237&signature=cfbca25f5fe210b3__;JSUl!!DZ3fjg!oa0yWHu4WaDeqycuBEcPRuw3vEvJrYARPPIAzJNsnxdet6loFCJ7O95nLR4BoT_L--M$> ORCID: 0000-0002-5301-8672 | Mendeley: francisco-bischoff | Google: tCeA0uUAAAAJ | ResearcherID: H-8261-2016 | ResearchGate: Francisco_Bischoff | CiênciaID B413-E0A0-DE8D | LinkedIn: franzbischoff On Sat, Jan 16, 2021 at 1:54 AM Dirk Eddelbuettel <e...@debian.org<mailto:e...@debian.org>> wrote: On 16 January 2021 at 01:35, Francisco Bischoff wrote: | 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). Hm but I think the Range class in Rcpp is not the same as R's seq(). It is used internally in a few places and may not generalize well to the 'b:-1:a' use. I had a quick look, and Armadillo may not have anything directly relevant either. linspace() is close but not quite the same. I would probably just write myself a little helper function. | 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; That can happen as template expressions can get in the way. Alternatives are maybe using Armadillo types for, again, just using a quick loop and printing elements. Rcpp has a lot of functions. But it doesn't have "all of R's functions" and should not be seen as aiming for that. Dirk -- https://dirk.eddelbuettel.com<https://urldefense.com/v3/__https:/mailtrack.io/trace/link/ec16eaacf00108f6b925d8cd55d469ea736d3313?url=https*3A*2F*2Fdirk.eddelbuettel.com&userId=3785237&signature=5ff5161e5ff16475__;JSUl!!DZ3fjg!oa0yWHu4WaDeqycuBEcPRuw3vEvJrYARPPIAzJNsnxdet6loFCJ7O95nLR4BxG2v_1M$> | @eddelbuettel | e...@debian.org<mailto:e...@debian.org> [Image removed by sender.]
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