Thanks everyone! I would have been banging my head around for quite a while and still wouldn't have come up with either solution. The function rle() is a good one to know!
Aloha, Tim Tim Clark Department of Zoology University of Hawaii --- On Wed, 2/10/10, Ben Tupper <ben.bigh...@gmail.com> wrote: > From: Ben Tupper <ben.bigh...@gmail.com> > Subject: Re: [R] Find each time a value changes > To: r-help@r-project.org > Cc: "Tim Clark" <mudiver1...@yahoo.com> > Date: Wednesday, February 10, 2010, 4:16 PM > Hi, > > On Feb 10, 2010, at 8:58 PM, Tim Clark wrote: > > > Dear List, > > > > I am trying to find each time a value changes in a > dataset. The > > numbers are variables for day vs. night values, so > what I am really > > getting is the daily sunrise and sunset. > > > > A simplified example is the following: > > > > x<-seq(1:100) > > y1<-rep(1,10) > > y2<-rep(2,10) > > y<-c(y1,y2,y1,y1,y1,y2,y1,y2,y1,y2) > > xy<-cbind(x,y) > > > > > > I would like to know each time the numbers change. > > Correct answer should be: > > x=1,11,21,51,61,71,81,91 > > > > I think this gets close... > > which(diff(y) != 0) > [1] 10 20 50 60 70 80 90 > > You'll need to fiddle to get exactly what you want. > > Cheers, > Ben > > > > > I would appreciate any help or suggestions. It > seems like it should > > be simple but I’m stuck! > > > > Thanks, > > > > Tim > > > > > > Tim Clark > > Department of Zoology > > University of Hawaii > > > > > > > > > > ______________________________________________ > > 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. > > ______________________________________________ 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.
