Hi catalin, I think what you are trying to do is to retrieve the original observations from the cumulated values. In that case Olivier's suggestion will do what you want:
c(x[1],diff(x)) Jim On Sat, Mar 5, 2016 at 1:59 AM, catalin roibu <catalinro...@gmail.com> wrote: > I mean the first row value > > În Vin, 4 mar. 2016, 16:15 Jeff Newmiller, <jdnew...@dcn.davis.ca.us> a > scris: > >> "Keep the first values" is imprecise, but mixing an absolute value with a >> bunch of differences doesn't usually work out well. I frequently choose >> among >> >> x <- sample( 10 ) >> dxright <- c( 0, diff(x) ) >> dxleft <- c( diff(x), 0 ) >> >> for calculation purposes depending on my needs. >> -- >> Sent from my phone. Please excuse my brevity. >> >> On March 4, 2016 3:28:08 AM PST, Olivier Crouzet < >> olivier.crou...@univ-nantes.fr> wrote: >> >Hi, >> > >> >(1) You should provide a minimal working example; >> > >> >(2) But anyway, does... >> > >> >x = sample(10) >> >c(x[1],diff(x)) >> > >> >... do what you want? >> > >> >Olivier. >> > >> > >> >On Fri, 4 Mar 2016 >> >13:22:07 +0200 catalin roibu <catalinro...@gmail.com> wrote: >> > >> >> Dear all! >> >> >> >> I want to calculate difference between successive values (cumulative >> >> values) with R. I used diff function, but I want to keep the first >> >> values. >> >> >> >> Please help me to solve this problem! >> >> >> >> Thank you! >> >> >> >> Best regards! >> >> >> >> CR >> >> >> >> -- >> >> >> >> - >> >> - >> >> Catalin-Constantin ROIBU >> >> >> >> Lecturer PhD, Forestry engineer >> >> Forestry Faculty of Suceava >> >> Str. Universitatii no. 13, Suceava, 720229, Romania >> >> office phone +4 0230 52 29 78, ext. 531 >> >> mobile phone +4 0745 53 18 01 >> >> FAX: +4 0230 52 16 64 >> >> silvic.usv.ro <http://www.usv.ro/> >> >> >> >> [[alternative HTML version deleted]] >> >> >> >> ______________________________________________ >> >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> >> 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. >> > >> >-- >> > Olivier Crouzet, PhD >> > Laboratoire de Linguistique de Nantes -- UMR6310 >> > CNRS / Université de Nantes >> > Chemin de la Censive du Tertre -- BP 81227 >> > 44312 Nantes cedex 3 >> > France >> > >> > http://www.lling.univ-nantes.fr/ >> > >> >______________________________________________ >> >R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> >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. >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. > > -- > > - > - > Catalin-Constantin ROIBU > > Lecturer PhD, Forestry engineer > > Forestry Faculty of Suceava > Str. Universitatii no. 13, Suceava, 720229, > office phone +4 0230 52 29 78, ext. 531 > mobile phone +4 0745 53 18 01 > +4 0766 71 76 58 > FAX: +4 0230 52 16 64 > silvic.usv.ro <http://www.usv.ro/> > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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.