>From the documentation I would have expected that the row locations start over at 1 for each group so that .I = 1:.N. but these are not equivalent.
On Tue, Apr 1, 2014 at 7:20 AM, Arunkumar Srinivasan <[email protected]> wrote: > 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 -- 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
