Hi, I'm a newbie when it comes to R, and I'm trying to figure out how to use vectorization as opposed to for loops. In particular, how can I create a function that is applied on each element of a row, but can access previous elements relative to that element?
My problem: I want to calculate something like x[i] = x[i] / x[i - 1] for each element of a vector x: ex. x <- data.frame(a = c(1:10)) # incorrect foo = function(y) { y[n] <- y[n] / y[n-1] } div <- lapply(x, foo) Any help would be greatly appreciated. Regards, -Amol Shelat [[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.