Sure. It’s on the list of tasks for this release as well, so I’ll have to work 
on it. Will try to put it up somewhere.

But the most useful thing you / anyone else could do is to provide / point to a 
data set (preferably in connection with flights, maybe weather?) that I can use 
as a 2nd table to explain joins. I’m not quite satisfied with the small 
artificial dataset that I’m using at the moment.

Also, the kind of questions that could be asked from that dataset using those 
two ( or more?) tables which requires joins (+ some other tasks) would be 
great! That’s the hardest part for me at the moment, not the explanations :-).

-- 
Arun

On 22 December 2015 at 14:42:38, stat quant ([email protected]) wrote:

I'd be happy to help.
Happy for me to have a look at it?

cheers 

On Tuesday, 22 December 2015, Arunkumar Srinivasan <[email protected]> 
wrote:
In the works. I’ve not yet managed to finish.

require(data.table)
A = data.table(x=1:2, y=3:4)
B = data.table(x=2:3, y=3:4)

anti-join:

A[!B, on="x"] # equivalently A[!B, .SD, on="x"]

semi-join:

A[B, .SD, nomatch=0L, on="x"]

-- 
Arun

On 21 December 2015 at 17:09:22, statquant3 ([email protected]) wrote:

Hello, is there a join vignette for data.table ?
I realize that I am now more and more using dplyr just for semi_join and
anti_join.
Is there any plan to write those sugar function ?
Happy to do it here and get feedback.

C.



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