# tidyr 1.1.3
* tidyr verbs no longer have "default" methods for lazyeval fallbacks. This
means that you'll get clearer error messages (#1036).
* `uncount()` error for non-integer weights and gives a clearer error message
for negative weights (@mgirlich, #1069).
* You can once again unnest dates (#1021, #1089).
* `pivot_wider()` works with data.table and empty key variables (@mgirlich, #1066).
* `separate_rows()` works for factor columns (@mgirlich, #1058).
# tidyr 1.1.2
* `separate_rows()` returns to 1.1.0 behaviour for empty strings
(@rjpatm, #1014).
# tidyr 1.1.1
* New tidyr logo!
* stringi dependency has been removed; this was a substantial dependency that
make tidyr hard to compile in resource constrained environments
(@rjpat, #936).
* Replace Rcpp with cpp11. See <https://cpp11.r-lib.org/articles/motivations.html>
for reasons why.
# tidyr 1.1.0
## General features
* `pivot_longer()`, `hoist()`, `unnest_wider()`, and `unnest_longer()` gain
new `transform` arguments; these allow you to transform values "in flight".
They are partly needed because vctrs coercion rules have become stricter,
but they give you greater flexibility than was available previously (#921).
* Arguments that use tidy selection syntax are now clearly documented and
have been updated to use tidyselect 1.1.0 (#872).
## Pivoting improvements
* Both `pivot_wider()` and `pivot_longer()` are considerably more performant,
thanks largely to improvements in the underlying vctrs code
(#790, @DavisVaughan).
* `pivot_longer()` now supports `names_to = character()` which prevents the
name column from being created (#961).
```{r}
df <- tibble(id = 1:3, x_1 = 1:3, x_2 = 4:6)
df %>% pivot_longer(-id, names_to = character())
```
* `pivot_longer()` no longer creates a `.copy` variable in the presence of
duplicate column names. This makes it more consistent with the handling
of non-unique specs.
* `pivot_longer()` automatically disambiguates non-unique ouputs, which can
occur when the input variables include some additional component that you
don't care about and want to discard (#792, #793).
```{r}
df <- tibble(id = 1:3, x_1 = 1:3, x_2 = 4:6)
df %>% pivot_longer(-id, names_pattern = "(.)_.")
df %>% pivot_longer(-id, names_sep = "_", names_to = c("name", NA))
df %>% pivot_longer(-id, names_sep = "_", names_to = c(".value", NA))
```
* `pivot_wider()` gains a `names_sort` argument which allows you to sort
column names in order. The default, `FALSE`, orders columms by their
first appearance (#839). In a future version, I'll consider changing the
default to `TRUE`.
* `pivot_wider()` gains a `names_glue` argument that allows you to construct
output column names with a glue specification.
* `pivot_wider()` arguments `values_fn` and `values_fill` can now be single
values; you now only need to use a named list if you want to use different
values for different value columns (#739, #746). They also get improved
errors if they're not of the expected type.
## Rectangling
* `hoist()` now automatically names pluckers that are a single string (#837).
It error if you use duplicated column names (@mgirlich, #834), and now uses
`rlang::list2()` behind the scenes (which means that you can now use `!!!`
and `:=`) (#801).
* `unnest_longer()`, `unnest_wider()`, and `hoist()` do a better job
simplifying list-cols. They no longer add unneeded `unspecified()` when
the result is still a list (#806), and work when the list contains
non-vectors (#810, #848).
* `unnest_wider(names_sep = "")` now provides default names for unnamed inputs,
suppressing the many previous name repair messages (#742).
## Nesting
* `pack()` and `nest()` gains a `.names_sep` argument allows you to strip outer
names from inner names, in symmetrical way to how the same argument to
`unpack()` and `unnest()` combines inner and outer names (#795, #797).
* `unnest_wider()` and `unnest_longer()` can now unnest `list_of` columns. This
is important for unnesting columns created from `nest()` and with
`pivot_wider()`, which will create `list_of` columns if the id columns are
non-unique (#741).
## Bug fixes and minor improvements
* `chop()` now creates list-columns of class `vctrs::list_of()`. This helps
keep track of the type in case the chopped data frame is empty, allowing
`unchop()` to reconstitute a data frame with the correct number and types
of column even when there are no observations.
* `drop_na()` now preserves attributes of unclassed vectors (#905).
* `expand()`, `expand_grid()`, `crossing()`, and `nesting()` once again
evaluate their inputs iteratively, so you can refer to freshly created
columns, e.g. `crossing(x = seq(-2, 2), y = x)` (#820).
* `expand()`, `expand_grid()`, `crossing()`, and `nesting()` gain a
`.name_repair` giving you control over their name repair strategy
(@jeffreypullin, #798).
* `extract()` lets you use `NA` in `into`, as documented (#793).
* `extract()`, `separate()`, `hoist()`, `unnest_longer()`, and `unnest_wider()`
give a better error message if `col` is missing (#805).
* `pack()`'s first argument is now `.data` instead of `data` (#759).
* `pivot_longer()` now errors if `values_to` is not a length-1 character vector
(#949).
* `pivot_longer()` and `pivot_wider()` are now generic so implementations
can be provided for objects other than data frames (#800).
* `pivot_wider()` can now pivot data frame columns (#926)
* `unite(na.rm = TRUE)` now works for all types of variable, not just character
vectors (#765).
* `unnest_wider()` gives a better error message if you attempt to unnest
multiple columns (#740).
* `unnest_auto()` works when the input data contains a column called `col`
(#959).
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