group-by.md
In dplyr: A Grammar of Data Manipulation

can't rename while partially `ungroup()`-ing (#6606)

Code
  ungroup(gdf, g2 = g)
Condition
  Error in `ungroup()`:
  ! Can't rename variables in this context.

select(group_by(.)) implicitly adds grouping variables (#170)

Code
  res <- select(group_by(mtcars, vs), mpg)
Message
  Adding missing grouping variables: `vs`

group_by works with zero-row data frames (#486)

Code
  x <- select(dfg, a)
Message
  Adding missing grouping variables: `g`

group_by() and ungroup() give meaningful error messages

Code
  df <- tibble(x = 1, y = 2)
  (expect_error(group_by(df, unknown)))
Output
  <error/rlang_error>
  Error in `group_by()`:
  ! Must group by variables found in `.data`.
  x Column `unknown` is not found.
Code
  (expect_error(ungroup(df, x)))
Output
  <error/rlib_error_dots_nonempty>
  Error in `ungroup()`:
  ! `...` must be empty.
  x Problematic argument:
  * ..1 = x
  i Did you forget to name an argument?
Code
  (expect_error(ungroup(group_by(df, x, y), z)))
Output
  <error/vctrs_error_subscript_oob>
  Error in `ungroup()`:
  ! Can't select columns that don't exist.
  x Column `z` doesn't exist.
Code
  (expect_error(group_by(df, z = a + 1)))
Output
  <error/dplyr:::mutate_error>
  Error in `group_by()`:
  i In argument: `z = a + 1`.
  Caused by error:
  ! object 'a' not found

group_by(add =) is defunct

Code
  group_by(df, x, add = TRUE)
Condition
  Error:
  ! The `add` argument of `group_by()` was deprecated in dplyr 1.0.0 and is now defunct.
  i Please use the `.add` argument instead.

group_by_prepare(add =) is defunct

Code
  group_by_prepare(df, x, add = TRUE)
Condition
  Error:
  ! The `add` argument of `group_by()` was deprecated in dplyr 1.0.0 and is now defunct.
  i Please use the `.add` argument instead.

group_by(.dots =) is defunct

Code
  group_by(df, .dots = "x")
Condition
  Error:
  ! The `.dots` argument of `group_by()` was deprecated in dplyr 1.0.0 and is now defunct.

group_by_prepare(.dots =) is defunct

Code
  group_by_prepare(df, .dots = "x")
Condition
  Error:
  ! The `.dots` argument of `group_by()` was deprecated in dplyr 1.0.0 and is now defunct.