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For example, data(iris) by(iris, quantcut(iris[,1]), function(x) sum(x[,1]/x[,2])) -- From: Ajay Shah <[EMAIL PROTECTED]> I know the `quantcut' function in the gregmisc package, and using it, I'm able to use functions like aggregate to compute the mean or sd() in each quartile. What if I have a data frame containing x and y, and I want to make quartiles by x, but then compute sum x / sum y in each quartile? How does one persuade aggregate to do this? ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
