Consider this example: > DT[1:4,,nomatch=0] a 1: a 2: b 3: c 4: NA Should it not return only the first 3 rows? It seems to be ignoring the nomatch=0. -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com