Wrap a function to return a value instead of an error

Create a modified version of .f that return a default value (otherwise) whenever an error occurs.

possibly(.f, otherwise = NULL, quiet = TRUE)

Arguments

.f

A function to modify, specified in one of the following ways:

• A named function, e.g. mean.

• An anonymous function, e.g. \(x) x + 1 or function(x) x + 1.

• A formula, e.g. ~ .x + 1. No longer recommended.

otherwise

Default value to use when an error occurs.

quiet

Hide errors (TRUE, the default), or display them as they occur?

Value

A function that takes the same arguments as .f, but returns a different value, as described above.

Adverbs

This function is called an adverb because it modifies the effect of a function (a verb). If you'd like to include a function created an adverb in a package, be sure to read faq-adverbs-export.

See also

Other adverbs: auto_browse(), compose(), insistently(), negate(), partial(), quietly(), safely(), slowly()

Examples

# To replace errors with a default value, use possibly().
list("a", 10, 100) |>
  map_dbl(possibly(log, NA_real_))
#> [1]       NA 2.302585 4.605170

# The default, NULL, will be discarded with `list_c()`
list("a", 10, 100) |>
  map(possibly(log)) |>
  list_c()
#> [1] 2.302585 4.605170