Hi, When using the aggregate function to aggregate a data.frame by one or more grouping variables I often have the problem, that I want the mean for some numeric variables but the unique value for factor variables.
So for example in this data-frame: data <- data.frame(x = rnorm(10,1,2), group = c(rep(1,5), rep(2,5)), gender =c(rep('m',5), rep('f',5))) aggregate(data, by=list(data$group), FUN=mean) I would like to have 'm' and 'f' in the third column, not NA. I see the problem, that it could happen that there is no unique factor level in a group – but is there an alternative function who at least tries what I am aiming at? That is; "aggregate the data.frame by a list of grouping variables, for numeric variables compute the mean, for factor variables return the unique factor value" Thanks! ______________________________________________ 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.