Ricardo, Thanks for the reply. Yes I agree. Eddi pointed out that, dt[, x := c(1:2)] when dt! for example! has a column y of length 5 will give a warning that it did not completely recycle. But when used with "by" it does not. This is obviously a bug. I will fix it to add the same warning for "by".
Arun. Sent from my iPad > On 23.10.2013, at 22:31, Ricardo Saporta <[email protected]> > wrote: > > I think we should have a warning iff it is not a "clean" recycle (ie, the > set gets cut off) > > In other words > > if (length(longer) %% length(shorter) != 0) > warning() > > > > Ricardo Saporta > Graduate Student, Data Analytics > Rutgers University, New Jersey > e: [email protected] > > > >> On Mon, Oct 21, 2013 at 2:18 PM, Arunkumar Srinivasan >> <[email protected]> wrote: >> Hi all, >> >> Here's the link to #4990: >> https://r-forge.r-project.org/tracker/index.php?func=detail&aid=4990&group_id=240&atid=975 >> >> I'm not sure there should be any warning here. A warning message is created >> in `:=` if the RHS that's assigned is "bigger" in length than the LHS. >> >> For ex: >> >> dt <- data.table(a=rep(1:2, c(5,2))) >> dt[, b := c(1,2,3), by=a] >> >> # creates warning that RHS is of length 3 and LHS is of length 2 for a ==2. >> Warning message: >> In `[.data.table`(dt, , `:=`(b, c(1, 2, 3)), by = a) : >> RHS 1 is length 3 (greater than the size (2) of group 2). The last 1 >> element(s) will be discarded. >> >> Other than that, there need not be any warning because it's being recycled. >> For example, >> >> x <- 1:5 >> x[c(TRUE, FALSE)] >> # [1] 1 3 5. >> >> Here, the number of elements of x are odd, but the recycling produces no >> warning. It may not exactly be the same issue, but to give an idea of silent >> recycling. >> >> What do you guys think? >> >> Arun >> >> >> _______________________________________________ >> datatable-help mailing list >> [email protected] >> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help >
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