Hi, To set a simple an clear picture of what I'd like to do, here is an example. I would like to calculate mean of column A and B bucketed by factor in column X in a data.frame. lapply or aggregate operates on a single column. I found dapply function in some package which doesn't seem to exist any more.
Is there anyway that I can accomplish something like this? Thank you so much in advance. adschai [[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.