[datatable-help] subsetting .SD

[Matthew Dowle]

Hi. There have been thoughts of adding .I for that. In the meantime
something like this should be faster:
DT[DT[,X1==max(X1),by='x,y,z'][[4]]]

> I  know that we shouldn't subset .SD, but I would like to return the row
> from each group that corresponds to a max value in one of the columns.
>  Here's how I'm doing it currently:
>
> maxrows<- df.dt[, .SD[which(X1== max(X1)),], by = list(Var1, Var2, Var3)]
>
> Is there a better way?
>
> Thank you kindly,
>
> Matthew
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