## Map family

The map(.x, .f) functions transforms each element of the vector .x with the function .f, returning a vector defined by the suffix (_lgl, _chr() etc). walk() is a variant for functions called primarily for their side-effects; it returns .x invisibly.

As well as functions, .f, can take numbers and characters (used as a shorthand for [[), and formulas (used as a succint function definition). See details in as_mapper()

map() map_lgl() map_int() map_dbl() map_chr() map_vec() walk()
Apply a function to each element of a vector
as_mapper()
Convert an object into a mapper function

## Map variants

A rich set of variants builds on the basic idea of map(): modify() modifies “in place”, returning a vector the same type as .x; map2() iterates over two vectors in parallel; pmap() (parallel map) iterates over a list of vectors; imap() (index map) is a shortcut for the common pattern map2(x, names(x)).

map_if() map_at()
Apply a function to each element of a vector conditionally
map_depth() modify_depth()
Map/modify elements at given depth
map2() map2_lgl() map2_int() map2_dbl() map2_chr() map2_vec() walk2()
Map over two inputs
pmap() pmap_lgl() pmap_int() pmap_dbl() pmap_chr() pmap_vec() pwalk()
Map over multiple input simultaneously (in "parallel")
modify() modify_if() modify_at() modify2() imodify()
Modify elements selectively
modify_tree()
Recursively modify a list
imap() imap_lgl() imap_chr() imap_int() imap_dbl() iwalk()
Apply a function to each element of a vector, and its index
lmap() lmap_if() lmap_at()
Apply a function to list-elements of a list

## Predicate functionals

A predicate function is a function that either returns TRUE or FALSE. The predicate functionals take a vector and a predicate function and do something useful.

detect() detect_index()
Find the value or position of the first match
every() some() none()
Do every, some, or none of the elements of a list satisfy a predicate?
has_element()
Does a list contain an object?
head_while() tail_while()
Find head/tail that all satisfies a predicate.
keep() discard() compact()
Keep/discard elements based on their values
keep_at() discard_at()
Keep/discard elements based on their name/position

## Plucking

Getting or setting a single element.

pluck() pluck<-() pluck_exists()
Safely get or set an element deep within a nested data structure
chuck()
Get an element deep within a nested data structure, failing if it doesn't exist
pluck_depth()
Compute the depth of a vector
modify_in() assign_in()
Modify a pluck location
attr_getter()
Create an attribute getter function

## Other vector transforms

A grab bag of useful tools for manipulating vectors.

accumulate() accumulate2()
Accumulate intermediate results of a vector reduction
list_c() list_cbind() list_rbind()
Combine list elements into a single data structure
list_flatten()
Flatten a list
list_assign() list_modify() list_merge()
Modify a list
list_simplify()
Simplify a list to an atomic or S3 vector
list_transpose()
Transpose a list
reduce() reduce2()
Reduce a list to a single value by iteratively applying a binary function

## Superseded

Superseded functions have been replaced by superior solutions, but due to their widespread use will not go away. However, they will not get any new features and will only receive critical bug fixes.

flatten() flatten_lgl() flatten_int() flatten_dbl() flatten_chr() flatten_dfr() flatten_dfc()
Flatten a list of lists into a simple vector
map_dfr() map_dfc() imap_dfr() imap_dfc() map2_dfr() map2_dfc() pmap_dfr() pmap_dfc()
Functions that return data frames
as_vector() simplify() simplify_all()
Coerce a list to a vector
transpose()
Transpose a list.

Adverbs modify the action of a function; they take a function as input and return a function with modified action as output.

auto_browse()
Wrap a function so it will automatically browse() on error
compose()
Compose multiple functions together to create a new function
insistently()
Transform a function to wait then retry after an error
negate()
Negate a predicate function so it selects what it previously rejected
partial()
Partially apply a function, filling in some arguments
possibly()
Wrap a function to return a value instead of an error
quietly()
Wrap a function to capture side-effects
safely()
Wrap a function to capture errors
slowly()
Wrap a function to wait between executions

## Misc

array_branch() array_tree()
Coerce array to list
rate_delay() rate_backoff() is_rate()
Create delaying rate settings
progress_bars
Progress bars in purrr