Try this: > which(diff(a) > 0) + 1 [1] 2 6 9 12 14 15
On Mon, May 24, 2010 at 6:02 AM, speretti <sabrina.pere...@gmail.com> wrote: > > Hi, > > I would like to receive help for the following matter: > > If I'm dealing with a numeric vectors containing increasing elements. > i.e. > > a<-c(1,2,2,2,2,3,3,3,4,4,4,5,5,6,7,7,7) > > There exist an efficient way to obtain an vector that indicates the position > of the changing element of "a"? > In this case it would be something like: > > index<-c(1,6,9,12,14,15) > > usually I'm used cycles to obtain boolean vectors of the same length of "a" > indicating the changing elements ...later I've muliplied them for their > numeric sequence and after that I've selected elements different from zero > ...it is quite long... > can you find an easier solution? > > Thank you for you help > -- > View this message in context: > http://r.789695.n4.nabble.com/switching-elements-of-a-vector-tp2228373p2228373.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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.
