The newest version of data.table has hit CRAN, and there are lots of great new features. Among them, a %notin% function, a new let function that can be used instead of := ( I wasn’t too fussed about this originally but have tried it a few times today and I may well adopt it - although I do like that := really stands out in my code when assigning / updating variables). The big feature is the new programming interface. I have blogged about programming on data.table before, but things have moved o...