Hi Kai, Perhaps something like this: kmdf<-data.frame(group=rep(c("exp","cont"),each=50), time=factor(rep(1:5,20)), condition=rep(rep(c("hot","cold"),each=25),2), value=sample(100:200,100)) for(timeindx in levels(kmdf$time)) { for(condindx in levels(kmdf$condition)) { cat("Time",timeindx,"Condition",condindx,"\n") subdat<-kmdf[kmdf$time == timeindx & kmdf$condition == condindx,] fit<-lm(value~group,subdat) print(summary(fit)) plot(subdat$group,subdat$value) by(subdat$value,subdat$group,mean) } }
Getting elegant output is another matter. Have a look at packages meant to produce fancier R output. Jim On Thu, Sep 1, 2016 at 7:58 AM, Kai Mx <govo...@gmail.com> wrote: > Hi all, > > I am having trouble wrapping my head around a probably simple issue: > > After using the reshape package, I have a melted dataframe with the columns > group (factor), time (int), condition (factor), value(int). > > These are experimental data. The data were obtained from different > treatment groups (group) under different conditions at different time > points. > > I would now like to perform ANOVA, boxplots and calculate means to compare > groups for all combinations of conditions and time points with something > like > > fit <- lm(value~group, data=[subset of data with combination of > condition/timepoint]) > summary (fit) > p <- ggplot([subset of data with combination of condition/timepoint], > aes(x= group, y=value)) + geom_boxplot () > print (p) > tapply ([subset of data with combination of condition/timepoint]$value, > subset of data with combination of condition/timepoint]$group, mean) > > How can I loop through these combinations and output the data in an elegant > way? > > Thanks so much! > > Best, > > Kai > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.