Hi Leon, On Fri, Jul 29, 2011 at 8:59 PM, Leon Baum <[email protected]> wrote: > > Hello, > > How do I perform a binary search on a data.table with an integer key? > > Say I create a data.table with > dt <- data.table(x=11:20, key="x") > > Passing the target integer 12 directly to i, > dt[12, ] > results in an error because data.table treats 12 as a row number. > > Surrounding 12 in quotes, > dt["12", ] > results in an error because data.table then expects a character key. > > The data.frame notation, > dt[x == 12, ] > works, but is slow because data.table appears to be just doing a vector > search.
You do it like so: R> dt[J(12)] > Am I missing something obvious? Not sure about "obvious" ... it's possible that you may have been inspired to try it after reading the intro + faq vignettes, but ... maybe not :-) Hope that helps, -steve -- Steve Lianoglou Graduate Student: Computational Systems Biology | Memorial Sloan-Kettering Cancer Center | Weill Medical College of Cornell University Contact Info: http://cbio.mskcc.org/~lianos/contact _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
