Dear R-experts:
I am using a function called AUC whose arguments are data, time, id, and dv. data is the name of the dataframe, time is the independent variable column name, id is the subject id and dv is the dependent variable. The function computes area under the curve by trapezoidal rule, for each subject id. I would like to embed this in aggregate to further subset by each Cycle, DoseDayNominal and Drug, but I can't seem to get the aggregate syntax correct. All the examples I can find use single column function such as mean, whereas this AUC function requires four arguments. Could someone kindly show me the syntax? This is what I've tried so far: AUC.DF<- aggregate(PKdata, list(PKdata$Cycle, PKdata$DoseDayNominal, PKdata$Drug), function(x,tm,pt,conc) {AUC(x)}, tm="TimeBestEstimate", pt="Pt", conc="ConcentrationBQLzero" ) AUC.DF<- aggregate(PKdata, list(PKdata$Cycle, PKdata$DoseDayNominal, PKdata$Drug), function(x) {AUC(x,"TimeBestEstimate", "Pt", "ConcentrationBQLzero" )} ) AUC syntax is: args(AUC) function (data, time = "TIME", id = "ID", dv = "DV") thanks Regards, Michael [[alternative HTML version deleted]] ______________________________________________ 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.