Hello, I'm trying to split my DF into a list using incremental loop. How can I avoid NULL elements in this list? DF <- data.frame(var1 = 1:10, var2 = 11:20, var3 = 21:30, var4 = 31:40) x <- list() i <- 1 while (i <= ncol(DF)-1) { x[[i]] <- DF[, i:c(i+1)] i <- i + 2 } x Many thanks, Lauri