>> You (as many before you) have overlooked the ave() function, which can >> replace the ordering as well the do.call(c,tapply(....)) >> > > Majority of questions on this list concern data manipulation. Many are > repetitive. "Overlooking" like that will always happen unless some > comprehensive data manipulation documentation is made. > I think many people would benefit if a specialized data.manip ref.card were > conceived.
I like the idea, but is a reference card really enough? To me, what most people need to tackle data manipulation problems is a broad strategy, not a list of useful functions. plyr is a codification of my most recent ideas on one such strategy: splitting a big data structure into smaller pieces, applying a function to each piece and then joining them back together. Just recognising your problem can be solved with this strategy is a big step forward, the functions in plyr just save you some typing and a bit of thought compared to doing it in base R. Recognising this strategy has helped me in my own data manipulation problems - many tasks with which I used to struggle are now easy to solve, not just because of plyr, but because I have a framework in which to think about the problem. But this is just one strategy and there must be many more common strategies waiting to be identified. I think working on this would be time better spent - describing a strategy gives people the tools to help themselves. (Of course this doesn't help the people who just want canned answers, but I'm less interested in helping them) Hadley -- http://had.co.nz/ ______________________________________________ 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.