R Data.Table Learning from Matt Dowle's Talk in 2014

Cited Matt Dowle’s data.table Talk from useR! 2014

In R Data.Table, column names can be used as variables.

For example,

DF[region == "USA", sum(population)]

Group by functionality

DF[region == "USA", sum(population), by = State]

Chaining functionality
DF[region == "USA", sum(population), by = State][order(-population),]

Assignment by reference
:=j 

Delete a column by reference
DF[, colToDelete := NULL]

Explicit copy functionality
DF2 <-  copy(DF)