Fixes for R 3.1.
Fix PROTECTion problems in C code revealed by rchk.
We noticed the following issues during reverse dependencies checks:
reduce() fails with this message:
Error: `.x` is empty, and no `.init` supplied, this is because
reduce() now returns
.x is empty. Fix the problem by supplying an appropriate argument to
.init, or by providing special behaviour when
.x has length 0.
The type predicates have been migrated to rlang. Consequently the
bare-type-predicates documentation topic is no longer in purrr, which might cause a warning if you cross-reference it.
purrr no longer depends on lazyeval or Rcpp (or dplyr, as of the previous version). This makes the dependency graph of the tidyverse simpler, and makes purrr more suitable as a dependency of lower-level packages.
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).
The plucking mechanism used for indexing into data structures with
map() has been extracted into the function
pluck(). Plucking is often more readable to extract an element buried in a deep data structure. Compare this syntax-heavy extraction which reads non-linearly:
to the equivalent pluck:
x %>% pluck(1, accessor, "foo")
as_mapper()because it is a tranformation that makes sense primarily for mapping functions, not in general (#298).
.nullhas been renamed to
.defaultto better reflect its intent (#298).
.defaultis returned whenever an element is absent or empty (#231, #254).
as_mapper() sanitises primitive functions by transforming them to closures with standardised argument names (using
rlang::as_closure()). For instance
+ is transformed to
function(.x, .y) .x + .y. This results in proper argument matching so that
, .x = 5)) produces
list(5 - 1, 5 - 2, ...).
Recursive indexing can now extract objects out of environments (#213) and S4 objects (#200), as well as lists.
attr_getter() makes it possible to extract from attributes like
map(list(iris, mtcars), attr_getter("row.names")).
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).
safely() and friends no longer capture interrupts: this means that you can now terminate a mapper using one of these with Escape or Ctrl + C (#314)
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.
map() functions now force their arguments in the same way that base R does for
lapply() (#191). This makes
map() etc easier to use when generating functions.
A new family of “indexed” map functions,
imap_lgl() etc, provide a short-hand for
map2(x, names(x)) or
map2(x, seq_along(x)) (#240).
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.)
modify() family returns the same output of the type as the input
.x. This is in contrast to the
map() family which always returns a list, regardless of the input type.
The modify functions are S3 generics. However their default methods should be sufficient for most classes since they rely on the semantics of
modify.default() is thus a shorthand for
x <- map(x, f).
at_depth() has been renamed to
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).
vec_depth() computes the depth (i.e. the number of levels of indexing) or a vector (#243).
reduce2_right() make it possible to reduce with a 3 argument function where the first argument is the accumulated value, the second argument is
.x, and the third argument is
stats::modifyList() to replace by position if the list is not named.(#201).
list_merge() operates similarly to
list_modify() but combines instead of replacing (#322).
The legacy function
update_list() is basically a version of
list_modify that evaluates formulas within the list. It is likely to be deprecated in the future in favour of a tidyeval interface such as a list method for
Thanks to @dchiu911, the unit test coverage of purrr is now much greater.
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
some() now return
NA if present in the input (#174).
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.
is_scalar_numeric() are deprecated because they don’t test for what you might expect at first sight.
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), and you can supply names in
... to reduce typing even more more (#316).
set_names() is now powered by
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
The function argument of
detect_index() have been renamed from
.f. This is because they have mapper semantics rather than predicate semantics.
This is a compatibility release with dplyr 0.6.0.
unslice()have been moved to purrrlyr. This is a bit of an aggresive change but it allows us to make the dependencies much lighter.
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:
x %||% yis shorthand for
if (is.null(x)) y else x(#109).
x %@% "a"is shorthand for
attr(x, "a", exact = TRUE)(#69).
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
flatten() is now type-stable and always returns a list. To return a simpler vector, use
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,
rep_along() generalise the idea of
is_null() is the snake-case version of
pmap() (parallel map) replaces
map_n() (#132), and has typed-variants suffixed
set_names() is a snake-case alternative to
setNames() with stricter equality checking, and more convenient defaults for pipes:
x %>% set_names() is equivalent to
setNames(x, x) (#119).
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
flatmap() -> use
map() followed by the appropriate
map3(x, y, z) ->
map_n(list(x, y, z));
walk3(x, y, z) ->pwalk(list(x, y, z))`