Hi Georg If you know which value belongs to which year you can use
tapply, by, aggregate family like: years<-rep(c(2000,2001,2002,2003), each=10) values<-(1:40) test<-cbind(years,values) test<-data.frame(test) aggregate(test$values,list(y=test$years),sum) Cheers Petr On 10 Feb 2005 at 11:01, Georg Hoermann wrote: > Hello world, > > I am actually transferring a course in data management for > students in biology, geography and agriculture > from statistica to R - it works > surprisingly well. If anyone is interested in my scratch/notepad > (in German language), please see > > www.hydrology.uni-kiel.de/~schorsch/statistik/statistik_datenauswertun > g.pdf > > (pages 40-52) > > The dataset is: > > www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv > > It contains a 10 year dataset. So far for introduction, now > comes the problem: > > we often need cumulative *annual* sums (sunshine, precipitation), > i.e. the sum > must reset to 0 at the beginning of the year. I know > of cumsum(), but I do not now how to split the dataset automagically > into annual pieces so I can cumsum() every year separately. I have the > strong hope that the solution is one of these one-liners which leave > the students with eyes wide open in surprise and makes them true > believers in the power of the command-line 8-). > > Thanks & Greetings > Georg > > > -- > Georg Hoermann, Luebeck, Germany > Tel. 0451/47 70 32, 0172/431 57 15, Penguin #189476 > > ______________________________________________ > 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 Petr Pikal [EMAIL PROTECTED] ______________________________________________ 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