[datatable-help] duplicated, with a key

[Joseph Voelkel]

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
joseph.voelkel at rit.edu

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