Library `data.table`'s default print method intentionally truncates table output for speed, basically concatenating `head` and `tail`.
In Zeppelin, this leads to poor alignment:
DT = data.table(a = seq_len(1e6))
I suspect this is the same issue as plagues matrix printing since `data.table` converts the object to be printed to a `matrix` first:
m = matrix(NA, 1e4, 10)