Nothing

```
context("empty groups")
df <- data_frame(
e = 1,
f = factor(c(1, 1, 2, 2), levels = 1:3),
g = c(1, 1, 2, 2),
x = c(1, 2, 1, 4)) %>%
group_by(e, f, g, .drop = FALSE)
test_that("filter and slice keep zero length groups", {
expect_equal(group_size(filter(df, f == 1)), c(2, 0, 0) )
expect_equal(group_size(slice(df, 1)), c(1, 1, 0) )
})
test_that("filtering and slicing retains labels for zero length groups", {
expect_equal(
count(filter(df, f == 1)),
tibble(
e = 1,
f = factor(1:3),
g = c(1, NA, NA),
n = c(2L, 0L, 0L)
) %>%
group_by(e, f)
)
expect_equal(
count(slice(df, 1)),
tibble(
e = 1,
f = factor(1:3),
g = c(1, 2, NA),
n = c(1L, 1L, 0L)
) %>%
group_by(e, f)
)
})
test_that("mutate keeps zero length groups", {
expect_equal( group_size(mutate(df, z = 2)), c(2, 2, 0) )
})
test_that("summarise returns a row for zero length groups", {
expect_equal( nrow(summarise(df, z = n())), 3L)
})
test_that("arrange keeps zero length groups",{
expect_equal( group_size(arrange(df)), c(2, 2, 0) )
expect_equal( group_size(arrange(df, x)), c(2, 2, 0) )
})
test_that("bind_rows respect the drop attribute of grouped df",{
gg <- bind_rows(df, df)
expect_equal(group_size(gg), c(4L,4L,0L))
})
test_that("joins respect zero length groups", {
df1 <- tibble(f = factor( c(1,1,2,2), levels = 1:3), x = c(1,2,1,4)) %>%
group_by(f)
df2 <- tibble(f = factor( c(2,2,3,3), levels = 1:3), y = c(1,2,3,4)) %>%
group_by(f)
expect_equal(group_size(left_join( df1, df2, by = "f")), c(2,4))
expect_equal(group_size(right_join( df1, df2, by = "f")), c(4,2))
expect_equal(group_size(full_join( df1, df2, by = "f")), c(2,4,2))
expect_equal(group_size(anti_join( df1, df2, by = "f")), c(2))
expect_equal(group_size(inner_join( df1, df2, by = "f")), c(4))
df1 <- tibble(f = factor( c(1,1,2,2), levels = 1:3), x = c(1,2,1,4)) %>%
group_by(f, .drop = FALSE)
df2 <- tibble(f = factor( c(2,2,3,3), levels = 1:3), y = c(1,2,3,4)) %>%
group_by(f, .drop = FALSE)
expect_equal(group_size(left_join( df1, df2, by = "f")), c(2,4,0))
expect_equal(group_size(right_join( df1, df2, by = "f")), c(0,4,2))
expect_equal(group_size(full_join( df1, df2, by = "f")), c(2,4,2))
expect_equal(group_size(anti_join( df1, df2, by = "f")), c(2,0,0))
expect_equal(group_size(inner_join( df1, df2, by = "f")), c(0,4,0))
})
test_that("n_groups respects zero-length groups (#341)", {
df <- tibble(x = factor(1:3, levels = 1:4)) %>% group_by(x, .drop = FALSE)
expect_equal(n_groups(df), 4)
})
test_that("summarise respects zero-length groups (#341)", {
df <- tibble(x = factor(rep(1:3, each = 10), levels = 1:4))
out <- df %>%
group_by(x, .drop = FALSE) %>%
summarise(n = n())
expect_equal(out$n, c(10L, 10L, 10L, 0L))
})
```

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