> what's different from: > > with(dat, tapply(x, list(name,case), sum)) > 1 2 3 > Joe 1 1 NA > John NA 1 NA > Karl NA NA 0 > Mike 1 0 1 > > and how to deal with this table ?
Well, the syntax is easier (once you have the data in the correct, molten, form), and more flexible for other tasks. It is surely better to learn a general purpose tool rather than a tool for a specific task. To use that table to answer the original question, you just need to look column by column for the desired patterns of 0's and 1's, eg. in case 1, Joe, Mike and Zoe all had ones. Perhaps I misunderstood the original question. Hadley ______________________________________________ R-help@stat.math.ethz.ch 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.
