Hello, I have a data frame with different groups (Time, Target, Conc) and each entry has a triplicate value of the measurements OD and ODnorm. How can I merge the triplicates into a single mean value? I tried the following: ``` df = data.frame(Time=rep(1, 9), Well=paste("A", 1:9, sep=""), OD=c(666, 815, 815, 702, 739, 795, 657, 705, 663), Target=rep("BACT", 9), Conc=c(1,1,1,2,2,2,3,3,3), ODnorm=c(9, 158, 158, 45, 82, 138, 0, 48, 6), stringsAsFactors = FALSE) aggregate(.~ODnorm, df, mean)
> aggregate(.~ODnorm, df, mean) ODnorm Time Well OD Target Conc 1 0 NA NA NA NA NA 2 6 NA NA NA NA NA 3 9 NA NA NA NA NA 4 45 NA NA NA NA NA 5 48 NA NA NA NA NA 6 82 NA NA NA NA NA 7 138 NA NA NA NA NA 8 158 NA NA NA NA NA aggregate(cbind(Time, Target, Conc) ~ ODnorm, df, mean) ODnorm Time Target Conc 1 0 NA NA NA 2 6 NA NA NA 3 9 NA NA NA 4 45 NA NA NA 5 48 NA NA NA 6 82 NA NA NA 7 138 NA NA NA 8 158 NA NA NA ``` Thank you. ______________________________________________ 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.