Yes, that's documented in ?duplicated.data.table. Matthew
On Sat, 2012-03-03 at 17:53 -0500, Joseph Voelkel wrote: > Is the second result by design? I found it confusing: > > x<-data.table(a=c(1:5,1:5),b=1:10) > sum(duplicated(x)) # 0, as expected > setkey(x,a) > sum(duplicated(x)) # 5 > Thanks, > Joe > > Joseph G. Voelkel, Ph.D. > > Graduate Program Chair, Center for Quality and Applied Statistics > > Kate Gleason College of Engineering > > Rochester Institute of Technology > > V 585-475-2231 > > F 585-475-5959 > > [email protected] > > > > CONFIDENTIALITY NOTE: The information transmitted, including > attachments, is intended only for the person(s) or entity to which it > is addressed and may contain confidential and/or privileged material. > Any review, retransmission, dissemination or other use of, or taking > of any action in reliance upon this information by persons or entities > other than the intended recipient is prohibited. If you received this > in error, please contact the sender and destroy any copies of this > information. > > > > > _______________________________________________ > datatable-help mailing list > [email protected] > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
