Suppose X is a data.frame with n obs and k vars, all variables are factors.
tab <- table(X) containes a k-dim array I would like to get a list from tab. This list is such that, each element contain the indexes corresponding to the observations which are in the same cell of this k-dim array. Of course, only for non empty cell. E.g. > set.seed(123) > X <- as.data.frame(matrix(rnorm(5000),100,5)) > X$V1 <- cut(X$V1, br=5) > X$V2 <- cut(X$V2, br=5) > X$V3 <- cut(X$V3, br=5) > X$V4 <- cut(X$V4, br=5) > X$V5 <- cut(X$V5, br=5) > tab <- table(X) > which(tab>0) -> cells > length(cells) [1] 94 thus, of course, 94 cells over 5^5 = 3125 are non empty. I would like a smart way (without reimplementing table/tabulate) to get the list of length 94 which contains the indexes of the obs in each cell Or, viceversa, a vector of length n which tells, observation by observation, which cell (out of the 3125) the observation is in. stefano ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
