[datatable-help] Speeding up column references with roll

[Gabor Grothendieck]

On Mon, Jun 30, 2014 at 1:00 PM, Arunkumar Srinivasan
<aragorn168b at gmail.com> wrote:
> Once again, has been fixed in 1.9.3. Now join requires `by=.EACHI`
> (explicit) to perform a by-without-by.
> https://github.com/Rdatatable/data.table/blob/master/README.md

The README would be easier to understand if DT was not undefined in
the README. As it stands none of the examples are runnable.