This documents differences between standard dplyr verbs and their data.table instantiation.

# S3 method for dtplyr_step
group_by(.data, ..., add = FALSE, arrange = TRUE)



A data.table


In group_by(), variables or computations to group by. In ungroup(), variables to remove from the grouping.


When FALSE, the default, group_by() will override existing groups. To add to the existing groups, use .add = TRUE.

This argument was previously called add, but that prevented creating a new grouping variable called add, and conflicts with our naming conventions.


If TRUE, will automatically arrange the output of subsequent grouped operations by group. If FALSE, output order will be left unchanged. In the generated data.table code this switches between using the keyby (TRUE) and by (FALSE) arguments.