Gabor, It's the same as in 1.8.10 and 1.9.2. What is contradicting in ?data.table? It says under .I: ".I is an integer vector length .N holding the row locations in x for this group."
The row locations in x for b=1,2,1,2 are 1,2,3,4 which then becomes 1,3 and 2,4 for this group => b=1 and b=2 respectively. Arun From: Gabor Grothendieck [email protected] Reply: Gabor Grothendieck [email protected] Date: April 1, 2014 at 1:09:23 PM To: [email protected] [email protected] Subject: [datatable-help] .I does not respect by In the following .I seems not to be within group. > dt <- data.table(a = 1:4, b = 1:2) > dt[, .I, by = b] b .I 1: 1 1 2: 1 3 3: 2 2 4: 2 4 > packageVersion("data.table") [1] '1.9.3' This seems contrary to ?data.table. -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
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