This task sounds almost uniquely poorly suited for R, but this has gotten better. For example, adding a column (did you append to the right or do an actual merg

This task sounds almost uniquely poorly suited for R, but this has gotten better. For example, adding a column (did you append to the right or do an actual merge/join?) used to require copying the previous table but doesn't any more. I wonder if you tried doing things like: * preallocate a list, then do.call(cbind, your_data) * Same as above, but with some of the faster alternatives to cbind like dplyr::bind_cols or data.table::cbind * Use data.table, which has far faster joins than base R (so does dplyr) if you were doing a true merge/join If it was truly just adding a column rom each file together into a file, these kinds of tasks are much better using UNIX tools, in my experience.