data.table is a nice option for retaining the familiarity of a dataframe while
opening the door for pass-by-reference semantics and a more SQL-like query
language. The literature is really wonderful too providing all levels of detail
ranging from the 10-minute introduction to the entirety of the API itself.
The 10-minute introduction is really revealing of things that you would probably
enjoy in your personal analytical workflow whether you obtain them with
data.table or elsewhere. The short introduction is also revealing that whatever
solution you choose requires sincere and focused mastery in order to truly
utilize its power without making major, major mistakes.