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[Documentation] Use of the on= argument for joins #1623
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Started on the wiki content. Started at
setkey()as it seemed a bit weird to jump toon=without coverage of keys and JOINs first.
https://github.com/Rdatatable/data.table/wiki/KeysR has great infrastructure for keeping docs. I would advocate to put such doc as a part of the package, so in vignettes or new Rd manuals. I'm quite OK on keeping GH related docs (support/contribution/installation/etc.) as GH wiki, but strictly project related stuff within the project content. So I would move fread wiki to vignettes too at some point.
BTW. AFAIK Arun is working on joins vignettes, so probably he handledonargument there.Agreed - vignettes would be fantastic.
@arunsrinivasan, I'm happy to port content over via PR?
I think you've not seen f55d35b and a2cb83a ?
Also, recently added Secondary indices and Auto indexing explains the rationale for
on=argument along with examples.The next vignette joins will also focus on
on=, but I'm in the process of wrapping up non-equi joins. So most likely, it'll happen after that.In essence, on your points:
- Join vignette will be added (and I think it's better than Wiki). Keep track of Vignettes #944.
- Makes sense. Adding FAQ explaining just the rationale behind
on=argument would be great! - See links above.
@jangorecki on
fread, moving it to vignettes is the plan, yes.Noted point 2 in #944.
On keys, there's an entire vignette dedicated to it.. (and will be more with join vignette) why the wiki? Is it addressing something different?
The
on=argument for data.table has minimal documentation at present, and does not feature in FAQs. It is, of course, a rather hard to search for the term.I'd like to see the following:
on=