Try nested ifelse() statements to label the group ex. time$group=ifelse(time$time<5,NA, ifelse(time$time<9,1, ifelse(time$time<13,NA, ifelse(time$time<17,2,NA) ) ) )
Then use aggregate to find the max value. ex. time.max=aggregate(time$value,list(group=time$group),max) On 21-May-07, at 6:39 AM, Robert wrote: > Hi dear R users, > > I'm a R beginner and I have a basic question about sequential > treatments of lists. > > I have a time based (i.e. events are consecutive) list of values of > a biological property. > > Like : > > time value > 1 5 > 2 10 > 3 7 > 4 10 > 5 19 > 6 21 > 7 20 > 8 18 > 9 10 > 10 7 > 11 8 > 12 12 > 13 17 > 14 19 > 15 24 > 16 18 > 17 15 > 18 10 > 19 9 > [...] > > > And I have to define a threshold and to attach each event to his > group, i.e. values upper the threshold. > > Like, for a threshold value of 17 > > time value group > 1 5 NA > 2 10 NA > 3 7 NA > 4 10 NA > 5 19 1 > 6 21 1 > 7 20 1 > 8 18 1 > 9 10 NA > 10 7 NA > 11 8 NA > 12 12 NA > 13 17 2 > 14 19 2 > 15 24 2 > 16 18 2 > 17 15 NA > 18 10 NA > 19 9 NA > [...] > > > The only solution that I have found is to do a sequentially read > and write : > for(i in 1:length(my_events_list)) > { > [...] > } > > But I very slow. Do you have another ideas ? > > And after I need to extract maximum values for each group > Like : > group max_value > 1 21 > 2 24 > [...] > > and for each event which is part of a group to know if is't a > ascending phase or no. > > > Yes, lot of questions !! Sorry, but I think that the solution may > be unique. > > In advance, thank you a lot > > regards > > JS > > > > > > > > > ______________________________________________________________________ > _______ > > ______________________________________________ > R-help@stat.math.ethz.ch 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. -- Mike Lawrence Graduate Student, Dalhousie University Department of Psychology http://myweb.dal.ca/mc973993 "The road to wisdom? Well, it's plain and simple to express: Err and err and err again, but less and less and less." - Piet Hein ______________________________________________ R-help@stat.math.ethz.ch 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.