actually I found the issue. That was not related to data.table but because I'm comparing float values, it breaks all the time if I do not round() my values before. Basically I have values like 0,1, 1.5, 0.5 etc... I know it's bad to do that but I'm not the boss in this project ;-)
Just in case other users are reading my email, I can only advise to read that again and again: http://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html Best, David On Tue, Apr 9, 2013 at 11:39 AM, Matthew Dowle <[email protected]>wrote: > ** > > > > That's odd. Please provide result of sessionInfo() and str(DT). > > Matthew > > > > On 09.04.2013 11:32, David Bellot wrote: > > Hi, > > I have a data.table DT with one of the column named x and I other names, > let's say, a1, a2, ... aN. The key of this data.table is made of a1...aN. > > Later on, I aggregate my DT with x like this: > agg = DT[ , list(m=mean(y), c=length(y)), by = c("x") ] > > The problem is that "x" has 331 unique values as found by > length(unique(DT$x)) but my result "agg" only has 119 rows. I tried by > changing the key to "x" alone but the problem persists. My DT table has a > few millions rows by the way. > > I'm sure I'm missing something totally obvious :-( !!!! > > Any idea ? > Best, > David > > > >
_______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
