Sorry, obviously misread your help request. Jim's solution is what you're looking for.
On 21-May-07, at 12:56 PM, Mike Lawrence wrote: > 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. -- 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.