tests/testthat/_snaps/verb-slice.md

In dbplyr: A 'dplyr' Back End for Databases

slice, head and tail aren't available

Code
  lf %>% slice()
Condition
  Error in `slice()`:
  ! `slice()` is not supported on database backends.

Code
  lf %>% slice_head()
Condition
  Error in `slice_head()`:
  ! `slice_head()` is not supported on database backends.
  i Please use `slice_min()` instead.

Code
  lf %>% slice_tail()
Condition
  Error in `slice_tail()`:
  ! `slice_tail()` is not supported on database backends.
  i Please use `slice_max()` instead.

slice_min handles arguments

Code
  db %>% slice_min()
Condition
  Error in `slice_min()`:
  ! `order_by` is absent but must be supplied.

Code
  db %>% slice_min(id, prop = 0.5, with_ties = FALSE)
Condition
  Error in `slice_by()`:
  ! Can only use `prop` when `with_ties = TRUE`

Code
  db %>% slice_min(id, n = 1, na_rm = FALSE)
Condition
  Error in `slice_min()`:
  ! `na_rm = FALSE` isn't supported on database backends.
  i It must be TRUE instead.

slice_max orders in opposite order

Code
  db %>% slice_max()
Condition
  Error in `slice_max()`:
  ! `order_by` is absent but must be supplied.

Code
  db %>% slice_max(id, n = 1, na_rm = FALSE)
Condition
  Error in `slice_max()`:
  ! `na_rm = FALSE` isn't supported on database backends.
  i It must be TRUE instead.

slice_* can use data masking pronouns

Code
  lf %>% slice_max(x)
Output
  <SQL>
  SELECT `x`, `id`
  FROM (
    SELECT `df`.*, RANK() OVER (ORDER BY `x` DESC) AS `col01`
    FROM `df`
  ) AS `q01`
  WHERE (`col01` <= 1)
Code
  lf %>% slice_max(.data$x)
Output
  <SQL>
  SELECT `x`, `id`
  FROM (
    SELECT `df`.*, RANK() OVER (ORDER BY `x` DESC) AS `col01`
    FROM `df`
  ) AS `q01`
  WHERE (`col01` <= 1)
Code
  lf %>% slice_max(.data$x * .env$x)
Output
  <SQL>
  SELECT `x`, `id`
  FROM (
    SELECT `df`.*, RANK() OVER (ORDER BY `x` * -1 DESC) AS `col01`
    FROM `df`
  ) AS `q01`
  WHERE (`col01` <= 1)

slice_sample errors when expected

Code
  db %>% slice_sample(replace = TRUE)
Condition
  Error in `slice_sample()`:
  ! Sampling with replacement is not supported on database backends

Code
  db %>% slice_sample(weight_by = x)
Condition
  Error in `slice_sample()`:
  ! Weighted resampling is not supported on database backends

Code
  db %>% slice_sample(prop = 0.5)
Condition
  Error in `slice_sample()`:
  ! Sampling by `prop` is not supported on database backends

check_slice_size checks for common issues

Code
  lf %>% slice_sample(n = 1, prop = 1)
Condition
  Error in `slice_sample()`:
  ! Must supply exactly one of `n` and `prop` arguments.

Code
  lf %>% slice_sample(n = "a")
Condition
  Error in `slice_sample()`:
  ! `n` must be a single number.

Code
  lf %>% slice_sample(prop = "a")
Condition
  Error in `slice_sample()`:
  ! `prop` must be a single number

Code
  lf %>% slice_sample(n = -1)
Condition
  Error in `slice_sample()`:
  ! `n` must be a non-missing positive number.

Code
  lf %>% slice_sample(prop = -1)
Condition
  Error in `slice_sample()`:
  ! `prop` must be a non-missing positive number.

slice_helper by errors use correct error context and correct by_arg

Code
  slice_min(gdf, order_by = x, by = x)
Condition
  Error in `slice_min()`:
  ! Can't supply `by` when `data` is a grouped data frame.
Code
  slice_max(gdf, order_by = x, by = x)
Condition
  Error in `slice_max()`:
  ! Can't supply `by` when `data` is a grouped data frame.
Code
  slice_sample(gdf, n = 1, by = x)
Condition
  Error in `slice_sample()`:
  ! Can't supply `by` when `data` is a grouped data frame.

slice_min/max can order by multiple columns

Code
  lf %>% slice_min(tibble(x))
Output
  <SQL>
  SELECT `x`, `y`
  FROM (
    SELECT `df`.*, RANK() OVER (ORDER BY `x`) AS `col01`
    FROM `df`
  ) AS `q01`
  WHERE (`col01` <= 1)
Code
  lf %>% slice_min(tibble::tibble(x, y))
Output
  <SQL>
  SELECT `x`, `y`
  FROM (
    SELECT `df`.*, RANK() OVER (ORDER BY `x`, `y`) AS `col01`
    FROM `df`
  ) AS `q01`
  WHERE (`col01` <= 1)
Code
  lf %>% slice_min(data.frame(y, x))
Output
  <SQL>
  SELECT `x`, `y`
  FROM (
    SELECT `df`.*, RANK() OVER (ORDER BY `y`, `x`) AS `col01`
    FROM `df`
  ) AS `q01`
  WHERE (`col01` <= 1)

Code
  lf %>% slice_max(tibble(x))
Output
  <SQL>
  SELECT `x`, `y`
  FROM (
    SELECT `df`.*, RANK() OVER (ORDER BY `x` DESC) AS `col01`
    FROM `df`
  ) AS `q01`
  WHERE (`col01` <= 1)
Code
  lf %>% slice_max(tibble::tibble(x, y))
Output
  <SQL>
  SELECT `x`, `y`
  FROM (
    SELECT `df`.*, RANK() OVER (ORDER BY `x` DESC, `y` DESC) AS `col01`
    FROM `df`
  ) AS `q01`
  WHERE (`col01` <= 1)
Code
  lf %>% slice_max(data.frame(y, x))
Output
  <SQL>
  SELECT `x`, `y`
  FROM (
    SELECT `df`.*, RANK() OVER (ORDER BY `y` DESC, `x` DESC) AS `col01`
    FROM `df`
  ) AS `q01`
  WHERE (`col01` <= 1)

slice_min/max informs if order_by uses c()

Can't use `c()` in `slice_min()`
i Did you mean to use `tibble(x, y)` instead?

dbplyr documentation built on Oct. 26, 2023, 9:06 a.m.