A list or atomic vector.

Level of .x to map on. Use a negative value to count up from the lowest level of the list.

• map_depth(x, 0, fun) is equivalent to fun(x).

• map_depth(x, 1, fun) is equivalent to x <- map(x, fun)

• map_depth(x, 2, fun) is equivalent to x <- map(x, ~ map(., fun))

A function, formula, or vector (not necessarily atomic).

If a function, it is used as is.

If a formula, e.g. ~ .x + 2, it is converted to a function. There are three ways to refer to the arguments:

• For a single argument function, use .

• For a two argument function, use .x and .y

• For more arguments, use ..1, ..2, ..3 etc

This syntax allows you to create very compact anonymous functions.

If character vector, numeric vector, or list, it is converted to an extractor function. Character vectors index by name and numeric vectors index by position; use a list to index by position and name at different levels. If a component is not present, the value of .default will be returned.

Additional arguments passed on to the mapped function.