data.table package overview

data.table is an R package that provides an extension of data.frame object called data.table. The package was developed by M Dowle, T Short, S Lianoglou, A Srinivasan with contributions from R Saporta, E Antonyan and offers:

_Fast aggregation of large data

_Fast ordered joins

_Fast modify/add/delete columns

_Fast file reader


You can read more information about it here

and my simple summary here