Wrap the j-exp with print. It will help you identify what the issue is. Arun
> On 27 Aug 2015, at 13:58, Frank S. <[email protected]> wrote: > > Hello everyone, > > I can execute my R code but I obtain a warning message and I do not know how > to avoid it. > Let's consider, just by way of example, the following data table with 2 > subjects under study: > > DT <- data.table(id=c(2,2,2,11,11), > start=c(rep(as.Date("2007-01-01"),3),rep(as.Date("2010-09-30"),2)), > visit=c("2007-03-01","2008-07-15","2008-11-17","2010-10-15","2011-05-17"), > end=c(rep(as.Date("2009-05-01"),3),rep(as.Date("2012-03-25"),2))) > > I get a new data table which assigns a fictitious visit on each 31 December > between > the dates "start" and "end" corresponding to each individual: > > DT.new <- unique(DT[,list(start, > visit=as.Date(c(paste0(year(start[1]):(year(end[1])-1),"-12-31"))), > end), by=id]) > > Warning messages: > In `[.data.table`(DT, , list(start, visit = > as.Date(c(paste0(year(start[1]):(year(end[1]) - : > Column 2 of result for group 1 is length 2 but the longest column in this > result is 3. Recycled leaving remainder of 1 items. This warning is once only > for the first group with this issue. > > The R code works, but how can I avoid the warning? > > Many thanks for any suggestion!! > _______________________________________________ > datatable-help mailing list > [email protected] > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
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