Those are great solutions. Thanks so much for your help. Yours, Alan
On Sun, Apr 25, 2010 at 11:43 AM, David Winsemius <dwinsem...@comcast.net> wrote: > > On Apr 25, 2010, at 2:22 PM, Chuck Cleland wrote: > >> On 4/25/2010 2:10 PM, Alan Lue wrote: >>> >>> Hi, >>> >>> Is there a way to specify the last element of a vector, similar to "end" >>> in >>> MATLAB? >>> >>> v[end] >>> >>> would be MATLAB for >>> >>> v(length(v)) >>> >>> in R. >>> >>> While `v(length(v))' does yield the last element, that approach fails in >>> the >>> following, >>> >>> rep(v, each=2)[-c(1,length(v))] > > Cleland's example works, but I thought you might be interested in ideas > about why your approach did not. The length of you rep-ed vector was twice > as long as the original so this method, which only adds a factor of two to > the length argument, succeeds: > >> rep(v, each=2)[-c(1,2*length(v))] > [1] 1 2 2 3 3 4 > > -- > David. > >>> >>> which is meant to duplicate all elements of `v' except for the first and >>> last. (I.e., if `v <- 1:4', then we want '1 2 2 3 3 4'.) >> >> v <- 1:4 >> >> rep(v, c(1, rep(2, length(v) - 2), 1)) >> [1] 1 2 2 3 3 4 >> >>> So the question is, is there a better way specify the last element of a >>> vector? If not, is there a better way to duplicate all elements of a >>> vector >>> except for the first and last? (I know you can achieve this using two >>> lines, but I'm writing because I want to do it using one.) >>> >>> Alan >> >> -- >> Chuck Cleland, Ph.D. >> NDRI, Inc. (www.ndri.org) >> 71 West 23rd Street, 8th floor >> New York, NY 10010 >> tel: (212) 845-4495 (Tu, Th) >> tel: (732) 512-0171 (M, W, F) >> fax: (917) 438-0894 >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > David Winsemius, MD > West Hartford, CT > > -- Alan Lue Master of Financial Engineering UCLA Anderson School of Management ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.