Same basic philosophy as group_by_prepare(): lazy_dots comes in, list of data and vars (character vector) comes out.

*_prepare() performs standard manipulation that is needed prior to actual data processing. They are only be needed by packages that implement dplyr backends.

distinct_prepare(.data, vars, group_vars = character(),
  .keep_all = FALSE)

group_by_prepare(.data, ..., .dots = list(), add = FALSE)

Value

A list

data

Modified tbl

groups

Modified groups