I used the dplyr do function to apply a kernel regression smoother to a 3 column data table (grouping index, x, y) with about 7 M rows and 45000 groups.
This runs quickly, about 1-2 minutes. It creates an data table (44,326 by 2) - grouping index, kernel smoothing output. The kernel smoothing output is a list of two element lists (x, smoothed y). I used a for loop to unlist this into a data table. for (i in 1:nrow(do object)) { df <- bind_rows(list(df, data.frame(grouping index = do object[i], x = do object[[i]]$x, y = do object[[i]]$smoothed y))) } This takes about 100 minutes. Any guidance for a faster (more elegant?) solution will be appreciated. Nathan ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.