purrr no longer depends on dplyr, lazyeval, or Rcpp. This makes the dependency graph of the tidyverse simpler, and makes purrr more suitable as a dependency of lower-level packages. This means that data-frame based mappers (
unslice()) have been moved to a new package, purrrlyr. This is a bit of an aggressive change but it needed to be done, and in this case I think it’s better to rip the band aid off quickly.
There have also been two changes to eliminate name conflicts between purrr and dplyr:
split_by() have been removed.
order_by() conflicted with
dplyr::order_by() and the complete family doesn’t feel that useful. Use tibbles instead (#217).
contains() has been renamed to
has_element() to avoid conflicts with dplyr (#217).
as_function() is now
as_mapper() because it is a tranformation that makes sense primarily for mapping functions, not in general (#298).
.null has been renamed to
.default to better reflect its intent (#298).
.default is returned whenever an element is absent or empty (#231, #254).
Recursive indexing can now extract objects out of environments (#213) and S4 objects (#200), as well as lists.
The argument list for formula-functions has been tweaked so that you can refer to arguments by position with
..2, and so on. This makes it possible to use the formula shorthand for functions with more than two arguments (#289).
All map functions now treat
NULL the same way as an empty vector (#199), and return an empty vector if any input is an empty vector.
The data frame suffix
_df has been (soft) deprecated in favour of
_dfr to more clearly indicate that it’s a row-bind. All variants now also have a
_dfc for column binding (#167). (These will not be terribly useful until
dplyr::bind_cols() have better semantics for vectors.)
map() always returns a list, regardless of the input type. A new
modify() family returns the same output of the type as the input
.x. They rely on the semantics of
modify() is shorthand for
x <- map(x, f).
modify_depth() gains new
.ragged argument, and negative depths are now computed relative to the deepest component of the list (#236).
auto_browse(f) returns a new function that automatically calls
f throws an error (#281).
depth() computes the depth (i.e. the number of levels of indexing) or a vector (#243).
All predicate functions are re-exported from rlang (#124).
compact() now works with standard mapper conventions (#282).
cross_n() has been renamed to
_n suffix was removed for consistency with
pmap() (originally called
map_n() at the start of the project) and
transpose() (originally called
cross_d() has been renamed to
cross_df() for consistency with
invoke() uses a more robust approach to generate the argument list (#249) It no longer uses lazyeval to figure out which enviroment a character
f comes from.
reduce() now throws an error if
.x is empty and
.init is not supplied.
zip_n() have been removed.
pmap() coerces data frames to lists to avoid the expensive
[.data.frame which provides security that is unneeded here (#220).
rdunif() checks its inputs for validity (#211).
set_names() can now take a function to tranform the names programmatically (#276).
safely() now actually uses the
quiet argument (#296).
transpose() now matches by name if available (#164). You can override the default choice with the new
Fix for dev tibble support.
as_function() now supports list arguments which allow recursive indexing using either names or positions. They now always stop when encountering the first NULL (#173).
reduce correctly pass extra arguments to the worker function.
as_function() gains a
.null argument that for character and numeric values allows you to specify what to return for null/absent elements (#110). This can be used with any map function, e.g.
map_int(x, 1, .null = NA)
as_function() is now generic.
is_function() that returns
TRUE only for regular functions.
Fix crash on GCC triggered by
There are two handy infix functions:
accumulate() has been added to handle recursive folding. It is shortand for
Reduce(f, .x, accumulate = TRUE) and follows a similar syntax to
reduce() (#145). A right-hand version
accumulate_right() was also added.
map_df() row-binds output together. It’s the equivalent of
invoke() has been overhauled to be more useful: it now works similarly to
.x is NULL, and hence
map_call() has been deprecated.
invoke_map() is a vectorised complement to
invoke() (#125), and comes with typed variants
zip_n() (#128). The name more clearly reflects the intent (transposing the first and second levels of list). It no longer has fields argument or the
.simplify argument; instead use the new
possibly() are experimental functions for working with functions with side-effects (e.g. printed output, messages, warnings, and errors) (#120).
safely() is a version of
try() that modifies a function (rather than an expression), and always returns a list with two components,
is_null() is the snake-case version of
We are still figuring out what belongs in dplyr and what belongs in purrr. Expect much experimentation and many changes with these functions.
map() now always returns a list. Data frame support has been moved to
dmap(). The latter supports sliced data frames as a shortcut for the combination of
x %>% by_slice(dmap, fun, .collate = "rows"). The conditional variants
dmap_if() also support sliced data frames and will recycle scalar results to the slice size.
map_rows() has been renamed to
invoke_rows(). As other rows-based functionals, it collates results inside lists by default, but with column collation this function is equivalent to
The rows-based functionals gain a
.to option to name the output column as well as a
.collate argument. The latter allows to collate the output in lists (by default), on columns or on rows. This makes these functions more flexible and more predictable.
as_function(), which converts formulas etc to functions, is now exported (#123).
rerun() is correctly scoped (#95)
update_list() can now modify an element called
map*() now use custom C code, rather than relying on
mapply() etc. The performance characteristcs are very similar, but it allows us greater control over the output (#118).
map_lgl() now has second argument