as_function {rlang}R Documentation

Convert to function or closure

Description

Usage

as_function(x, env = caller_env())

as_closure(x, env = caller_env())

Arguments

x

A function or formula.

If a function, it is used as is.

If a formula, e.g. ~ .x + 2, it is converted to a function with two arguments, .x or . and .y. This allows you to create very compact anonymous functions with up to two inputs.

env

Environment in which to fetch the function in case x is a string.

Examples

f <- as_function(~ . + 1)
f(10)

# Primitive functions are regularised as closures
as_closure(list)
as_closure("list")

# Operators have `.x` and `.y` as arguments, just like lambda
# functions created with the formula syntax:
as_closure(`+`)
as_closure(`~`)

[Package rlang version 0.2.2 Index]