Assuming DF is a data frame like this: DF <- data.frame(V1 = c(1, 0, 1, 0), V2 = c(1, 1, 1, 1), V3 = c(0, 1, 1, 1), V4 = c(0, 0, 0, 1))
# try this: head(rowSums((rbind(0, cummax(DF)) < rbind(cummax(DF), 0))), -1) On Sun, Dec 21, 2008 at 8:36 PM, Keun-Hyung Choi <khc...@sfsu.edu> wrote: > Dear helpers, > > > > I'm using R version 2.8.0. > > Suppose that I have a small data set like below. > > [,1] [,2] [,3] [,4] > > a 1 1 0 0 > > b 0 1 1 0 > > c 1 1 1 0 > > d 0 1 1 1 > > > > First, I'd like to find row sum of values uniquely present in each row, but > only sequentially from the top row, meaning that if the value is shown in > the above row(s) already, the same value in the following row shouldn't be > added into the sum. > > The result should be like this: > > > > row.sum > > [1] 2 1 0 1 > > > > And if a and c were swapped, the row.sum is 3 0 0 1 > > > > Second, I'd like to randomly reorder the rows, and repeat calculating > row.sum again, for many times less than all combinations possible (4! In > this case), kind of simulation, and store the results into a matrix. > > Thanks. > > Keun-Hyung > > > > > > > > > > > [[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. > ______________________________________________ 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.