[R] How to generate a particular sequence ?
Dear R, I have a vector, say a = c(1,2,4,5,6,8). Can I generate a vector or array (2-by-3-by-3) of this form c(1,2,1,2,1,2,4,5,4,5,4,5,6,8,6,8,6,8), in which every two elements in a have been repeated twice? I am to stupid today and could not figure this simple question out... Many many thanks! Feng -- Feng Li Department of Statistics Stockholm University 106 91 Stockholm, Sweden http://feng.li/ [[alternative HTML version deleted]] __ 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.
Re: [R] How to generate a particular sequence ?
On 09/13/2010 07:19 PM, Feng Li wrote: Dear R, I have a vector, say a = c(1,2,4,5,6,8). Can I generate a vector or array (2-by-3-by-3) of this form c(1,2,1,2,1,2,4,5,4,5,4,5,6,8,6,8,6,8), in which every two elements in a have been repeated twice? I am to stupid today and could not figure this simple question out... Many many thanks! Hi Feng, I would take a quick look at the help for rep and c, but I would first suggest that you count the number of times that the elements are to be repeated. While you have made the definition of the problem reasonably clear with your example, there are an awful lot of combinations of every two elements of a, whether you want to repeat them two or three times. Jim __ 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.
Re: [R] How to generate a particular sequence ?
On 13-Sep-10 09:19:21, Feng Li wrote: Dear R, I have a vector, say a = c(1,2,4,5,6,8). Can I generate a vector or array (2-by-3-by-3) of this form c(1,2,1,2,1,2,4,5,4,5,4,5,6,8,6,8,6,8) in which every two elements in a have been repeated twice? I am to stupid today and could not figure this simple question out... Many many thanks! Feng A possible solution (somewhat generalisable): a - c(1,2,4,5,6,8) Reps - 3 pairs - matrix(a,nrow=2) as.vector(pairs[,rep(c(1,2,3),each=Reps)]) # [1] 1 2 1 2 1 2 4 5 4 5 4 5 6 8 6 8 6 8 (By the way, you have 3 repetitions but wrote twice -- I assume you meant thrice but the above generalises to 2 repetitions ... :) Ted. E-Mail: (Ted Harding) ted.hard...@manchester.ac.uk Fax-to-email: +44 (0)870 094 0861 Date: 13-Sep-10 Time: 10:42:46 -- XFMail -- __ 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.
Re: [R] How to generate a particular sequence ?
Ted Harding ted.hard...@manchester.ac.uk wrote in message news:xfmail.100913104250.ted.hard...@manchester.ac.uk... On 13-Sep-10 09:19:21, Feng Li wrote: Dear R, I have a vector, say a = c(1,2,4,5,6,8). Can I generate a vector or array (2-by-3-by-3) of this form c(1,2,1,2,1,2,4,5,4,5,4,5,6,8,6,8,6,8) in which every two elements in a have been repeated twice? I am to stupid today and could not figure this simple question out... Many many thanks! Feng A possible solution (somewhat generalisable): a - c(1,2,4,5,6,8) Reps - 3 pairs - matrix(a,nrow=2) as.vector(pairs[,rep(c(1,2,3),each=Reps)]) # [1] 1 2 1 2 1 2 4 5 4 5 4 5 6 8 6 8 6 8 (By the way, you have 3 repetitions but wrote twice -- I assume you meant thrice but the above generalises to 2 repetitions ... :) Ted. The pedant in me couldn't resist asking: If he'd said repeated once would you expect only one occurence of each pair? Sorry. I'll get my coat Keith J __ 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.
Re: [R] How to generate a particular sequence ?
Sorry. It was my typo. Should be three times as it in the example. Feng On Mon, Sep 13, 2010 at 11:32 AM, Jim Lemon j...@bitwrit.com.au wrote: On 09/13/2010 07:19 PM, Feng Li wrote: Dear R, I have a vector, say a = c(1,2,4,5,6,8). Can I generate a vector or array (2-by-3-by-3) of this form c(1,2,1,2,1,2,4,5,4,5,4,5,6,8,6,8,6,8), in which every two elements in a have been repeated twice? I am to stupid today and could not figure this simple question out... Many many thanks! Hi Feng, I would take a quick look at the help for rep and c, but I would first suggest that you count the number of times that the elements are to be repeated. While you have made the definition of the problem reasonably clear with your example, there are an awful lot of combinations of every two elements of a, whether you want to repeat them two or three times. Jim -- Feng Li Department of Statistics Stockholm University 106 91 Stockholm, Sweden http://feng.li/ [[alternative HTML version deleted]] __ 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.
Re: [R] How to generate a particular sequence ?
Thanks. That's what I want. Sorry for the typo:) Feng On Mon, Sep 13, 2010 at 11:42 AM, Ted Harding ted.hard...@manchester.ac.ukwrote: On 13-Sep-10 09:19:21, Feng Li wrote: Dear R, I have a vector, say a = c(1,2,4,5,6,8). Can I generate a vector or array (2-by-3-by-3) of this form c(1,2,1,2,1,2,4,5,4,5,4,5,6,8,6,8,6,8) in which every two elements in a have been repeated twice? I am to stupid today and could not figure this simple question out... Many many thanks! Feng A possible solution (somewhat generalisable): a - c(1,2,4,5,6,8) Reps - 3 pairs - matrix(a,nrow=2) as.vector(pairs[,rep(c(1,2,3),each=Reps)]) # [1] 1 2 1 2 1 2 4 5 4 5 4 5 6 8 6 8 6 8 (By the way, you have 3 repetitions but wrote twice -- I assume you meant thrice but the above generalises to 2 repetitions ... :) Ted. E-Mail: (Ted Harding) ted.hard...@manchester.ac.uk Fax-to-email: +44 (0)870 094 0861 Date: 13-Sep-10 Time: 10:42:46 -- XFMail -- -- Feng Li Department of Statistics Stockholm University 106 91 Stockholm, Sweden http://feng.li/ [[alternative HTML version deleted]] __ 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.
