Will this do it for you: > nrows <- 10 > ncols <- 10 > mat <- matrix(sample(0:1, nrows * ncols, TRUE), nrow=nrows, ncol=ncols) > mat [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [1,] 1 0 1 1 1 0 0 0 0 0 [2,] 0 0 0 0 0 0 0 1 1 0 [3,] 0 1 0 0 1 1 1 1 1 1 [4,] 0 1 1 1 0 0 0 0 1 1 [5,] 0 0 1 0 1 1 1 0 0 0 [6,] 1 0 1 0 0 0 1 0 0 0 [7,] 0 0 1 0 0 1 0 0 1 1 [8,] 1 0 1 0 0 0 1 1 1 0 [9,] 0 1 0 1 0 1 1 0 0 0 [10,] 0 1 1 1 1 0 0 0 1 0 > mask <- rep(1, ncols) > for (i in 1:nrows){ + print(sum(mask & mat[i,])) + mask <- mask & !mat[i,] + } [1] 4 [1] 2 [1] 4 [1] 0 [1] 0 [1] 0 [1] 0 [1] 0 [1] 0 [1] 0
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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.