Joins vignettes aren't done yet 😔. It is planned for v1.9.8. Will work on it after wrapping up things I am working on now.
Arun -- Sent from my iPhone > On 09 Nov 2015, at 02:43, Stefano Grioni <[email protected]> wrote: > > Hello, > > As I was reading through the vignette on data handling and joins, it was not > immediately evident to me how to do an update on auto-join using only data > table. > > I have managed to do what I need using by using SQL, but I don't find it > particularly elegant and performance will probably be terrible on large > datasets: > > tmp <- sqldf("select a.Field1, a.Field2, a.Field3, b.Output from MyDataset a > INNER JOIN MyDataset b on a.Field1 =b.Field1 and a.Field2 = b.Field2+1and > a.Field3=b.Field3") > tmp <- as.data.table(tmp) > setkey(MyDataset, Field1, Field2, Field3) > setkey(tmp, Field1, Field2, Field3) > MyDataset[tmp,Field4 := i.Output, nomatch=0] > > I tried to do the same using twice the same data frame but I can't see how to > integrate the join condition on Field2 (see above). > > Is there an elegant way to address this? > > Many thanks > > Stefano > _______________________________________________ > datatable-help mailing list > [email protected] > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
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