Hi, For the sake of efficiency I am trying to do away from data frames and use lists instead. The two more frequently used operations on data frames are row subscripting "[" and "[<-" for which I want to find good (idiomatic) replacements. For x[i,j] extraction I came up with the following replacement: y = lapply(x[j], function(col) col[i]) which looks concise enough and is more efficient. However I couldn't think of anything elegant for y[i,j] = x. Suggestions? Thanks, Vadim