[datatable-help] "Within" Reversed column order?

[Yike Lu]

Yes, this looks ideal. Cheers

On 5/29/2012 11:47 AM, Matthew Dowle wrote:
> Yes. Now that := by group is implemented in 1.8.1, the next step would 
> be to make it multiple := by group, which can't be done efficiently by 
> chaining anyway. So, DT[,{newcol1:=colA+colB newcol2:=newcol1*2 
> },by=month(colC)] Where the 2nd := can use the result from the first 
> like that, too. Would that syntax be ok?
>> Or perhaps an overload on transform that allows {expr}.
> Maybe. Kinda getting hooked on := now, though.
>
> Matthew