lift_xy() is a composition helper. It helps you compose
functions by lifting their domain from a kind of input to another
kind. The domain can be changed from and to a list (l), a vector
(v) and dots (d). For example,
lift_ld(fun) transforms a
function taking a list to a function taking dots.
lift(..f, ..., .unnamed = FALSE) lift_dl(..f, ..., .unnamed = FALSE) lift_dv(..f, ..., .unnamed = FALSE) lift_vl(..f, ..., .type) lift_vd(..f, ..., .type) lift_ld(..f, ...) lift_lv(..f, ...)
A function to lift.
Default arguments for
A vector mold or a string describing the type of the
input vectors. The latter can be any of the types returned by
The most important of those helpers is probably
because it allows you to transform a regular function to one that
takes a list. This is often essential for composition with purrr
functional tools. Since this is such a common function,
lift() is provided as an alias for that operation.
Here dots should be taken here in a figurative way. The lifted
functions does not need to take dots per se. The function is
simply wrapped a function in
do.call(), so instead
of taking multiple arguments, it takes a single named list or
vector which will be interpreted as its arguments. This is
particularly useful when you want to pass a row of a data frame
or a list to a function and don't want to manually pull it apart
in your function.
These factories allow a function taking a vector to take a list
or dots instead. The lifted function internally transforms its
inputs back to an atomic vector. purrr does not obey the usual R
casting rules (e.g.,
c(1, "2") produces a character
vector) and will produce an error if the types are not
compatible. Additionally, you can enforce a particular vector
type by supplying
lift_ld() turns a function that takes a list into a
function that takes dots.
lift_vd() does the same with a
function that takes an atomic vector. These factory functions are
the inverse operations of
lift_vd() internally coerces the inputs of
an atomic vector. The details of this coercion can be controlled