Peter Dalgaard <[EMAIL PROTECTED]> napsal dne 08.10.2007 16:31:28: > Petr PIKAL wrote: > > Hi > > > > [EMAIL PROTECTED] napsal dne 08.10.2007 14:24:13: > > > > > >> Hi, > >> > >> I would like to fix the data in the following data.frame, and I am > >> having trouble coding this in R - help please! > >> > >> > >>> x > >>> > >> A B x y z > >> 1 1 10.0 100 1000 10000 > >> 2 2 19.8 200 2000 20000 > >> 3 3 20.1 300 3000 30000 > >> 4 4 20.3 400 4000 40000 > >> 5 5 30.0 500 5000 50000 > >> > >> Column B is the problem. > >> > >> The logic I need to apply (this is in pseudo code ... I don't know how > >> to do this in R) > >> > >> for all rows, r > >> if x$B[r] <= x$B[r-1] + a > >> then x$B[r] = x$B[r-1] > >> > >> i.e. If a=1, then I would end up with the data.frame > >> > >> > >>> x > >>> > >> A B x y z > >> 1 1 10.0 100 1000 10000 > >> 2 2 19.8 200 2000 20000 > >> 3 3 19.8 300 3000 30000 > >> 4 4 19.8 400 4000 40000 > >> 5 5 30.0 500 5000 50000 > >> > > > > [...] > > > > > >> b.na <- test$B > >> b.na[c(F,diff(test$B)<1)] <- NA > >> b.na > >> > It is not clear that this works. What if test$B[4] is 20.9 instead of 20.3? > > There are cases that just don't vectorize. Brute force may be the only > solution. It may be slow, but it is available.
That is what i meant with data in chunks. What if test$B looks like seq(1, 10, .1). I expected, maybe wrongly, that the data looks like (n1...nn, big step1, m1...mn, big step2, ....) and that David wants simply change this to NNNNNNN,MMMMM,.... And there are other ifs is B always increasing? > > X <- test$B > for (i in seq_along(X[-1])) > if (X[i] - X[i-1] < 1) > X[i] <- X[i-1] > test$B <- X X[i-1] is X[0] which does not work, you probably meant X[i+1] Regards Petr > > -- > O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B > c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K > (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 > ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 > > ______________________________________________ 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.
