Try this for the given data: you'll have to modify the group label trick a bit if row-numbers aren't even for each element of L, but it's not hard.
L <- list(`0` = matrix(rnorm(6), ncol = 2), `1` = matrix(rnorm(6), ncol = 2), `2` = matrix(rnorm(6), ncol = 2)) # Generally it's bad form to use numbers for names cbind(do.call(rbind, L), group = rep(as.double(names(L)), each = nrow(L[[1]])) Good luck, Michael 2011/11/23 Ernest Adrogué <nfdi...@gmail.com>: > Hello, > > I have this list of 2-d arrays: > > $`0` > k d > [1,] 0.2011962 4.019537 > [2,] 0.2020706 5.722719 > [3,] 0.2029451 7.959612 > > $`1` > k d > [1,] 0.3148325 2.606903 > [2,] 0.3160287 3.806665 > [3,] 0.3172249 5.419222 > > $`2` > k d > [1,] 0.2332536 4.949390 > [2,] 0.2342188 7.115258 > [3,] 0.2351840 9.955909 > > which I need to transform into a data frame like this one: > > k d group > [1,] 0.2011962 4.019537 0 > [2,] 0.2020706 5.722719 0 > [3,] 0.2029451 7.959612 0 > [1,] 0.3148325 2.606903 1 > [2,] 0.3160287 3.806665 1 > [3,] 0.3172249 5.419222 1 > [1,] 0.2332536 4.949390 2 > [2,] 0.2342188 7.115258 2 > [3,] 0.2351840 9.955909 2 > > Is there any R function that I can use? I know stack() but it only > works with vectors. > > Thank you! > Ernest > > ______________________________________________ > 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.
