Submitted by: Ricardo Saporta; Assigned to: Arun ; R-Forge link

I searched around for unname data.table and found this thread from v1.8.1

http://r.789695.n4.nabble.com/unname-does-not-work-with-data-table-anymore-td4521647.html

I'm encountering the following error in 1.8.11 and 1.8.10.

DT <- data.table(A = rep(LETTERS, 3), B = seq(78))
unname(DT)

data.frame analogous

DF <- data.frame(A = rep(LETTERS, 3), B = seq(78))
unname(DF)

Extra problem is that try does not catch the error:

inherits(try(unname(DT)), "try-error")

[1] FALSE

I thought the error might be just in print.data.table
Z <- unname(DT) # no error

but then again, maybe not:
setnames(Z, c("A", "B"))

Using setattr can put things back to normal

setattr(Z, "names", c("A", "B"))
Z

is it possible that the error is only

occurrenting when there are more than 20 rows?

unname( DT [1:21] ) # Error (21 rows)
unname( DT [2:22] ) # Error (21 rows)
unname( DT [2:21] ) # No Error (20 rows)

unname( DT [30:50] ) # Error (21 rows)
unname( DT [30:49] ) # No Error (20 rows)