[datatable-help] Writing a good "WHERE" statement

[Eduard Antonyan]

you could use Days %in% c(1,5,10,20,30,60,90) instead, or iff Days is the
first key J(c(1,5,10,20,30,60,90))


On Wed, Aug 14, 2013 at 9:30 AM, John Kerpel <john.kerpel2 at gmail.com> wrote:

> Folks:
>
> I've been working more and more in data.table and it gets better and
> better as I learn to use it....
>
> So my question is, in the following example, is the Where statement
> inefficient because I'm using "==" ?  (I just want to use the subsets where
> days are equal to the values in the statement)
>
> Should I do this another way? (Btw, I get exactly the right answer using
> this approach...)
>
> db <- DB4[
>
>   Days==1 | Days==5 | Days==10 | Days==20 | Days==30 | Days==60 | Days==90,
>
>   j =   {list(v=m_func(x,y,z))},
>
>   by= "Date,Indicator,Days"
>
>   ]
>
> If more detail is necessary, lmk. Date, Indicator, and Days are keys.
>
> Best,
>
> John
>
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