Petr PIKAL wrote: > 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] > > Drats!
Actually, I meant seq_along(X)[-1] i.e. 2:length(X), except if length(X) <= 1 (That's what you get for trying to get things right...) -- 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.
