Using the example in the link here are two one-liners: A <- c(2,3,4,1,2,3,4,1,1,2) x <- c(1,2)
# 1 - zoo library(zoo) which( rollapply(A, length(x), identical, x, fill = FALSE, align = "left") ) ## [1] 4 9 # 2 - Base R using conversion to character gregexpr(paste(x, collapse = ""), paste(A, collapse = ""))[[1]] ## [1] 4 9 ...snip ... On Fri, Oct 11, 2019 at 3:45 AM Morgan Morgan <morgan.email...@gmail.com> wrote: > > Hi All, > > I was looking for a function to find a small matrix inside a larger matrix > in R similar to the one described in the following link: > > https://www.mathworks.com/matlabcentral/answers/194708-index-a-small-matrix-in-a-larger-matrix > > I couldn't find anything. > > The above function can be seen as a "generalisation" of the "which" > function as well as the function described in the following post: > > https://coolbutuseless.github.io/2018/04/03/finding-a-length-n-needle-in-a-haystack/ > > Would be possible to add such a function to base R? > > I am happy to work with someone from the R core team (if you wish) and > suggest an implementation in C. > > Thank you > Best regards, > Morgan > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
