[datatable-help] updating subsets

[Sebastian Fischmeister]

> I think you should use a single data.table; it's much more straightforward
> in that case:
>
> qq <- data.table(runif(18),id=rep(1:2,each=9))
> qq[,freq:=.N,by=.(id,seq(nrow(qq))%/%5)]

Thanks for the idea, unfortunately I need lists. The example is just a
minimal example to show the problem. The actual code will use large
data.tables in lists and I want to eventually use mclapply to
parallelize the computation.

  Sebastian