Dear jeff6868, Here is one way:
ifelse(with(data, c(0, diff(mydata))) != 1, 0, 1) You could also take a look at ?rle HTH, Jorge.- On Mon, Dec 15, 2014 at 9:33 PM, jeff6868 <geoffrey_kl...@etu.u-bourgogne.fr > wrote: > > Hello dear R-helpers, > > I have a small problem in my algorithm. I have sequences of "0" and "1" > values in a column of a huge data frame, and I just would like to keep the > first value of each sequences of "1" values, such like in this example: > > data <- > > data.frame(mydata=c(0,0,0,1,1,1,1,1,0,0,0,0,1,1,1,0,0,0,0,1,1,1,1,1,1,1),final_wished_data=c(0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0)) > > Any easy way to do this? > > Thanks everybody! > > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/keep-only-the-first-value-of-a-numeric-sequence-tp4700774.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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.