Match/validate a set of conditions for an object and continue with the action associated with the first valid match.
Source:R/deprec-when.R
when.Rd
This function was deprecated in purrr 1.0.0 because it's not related to the
core purpose of purrr. You can pull your code out of a pipe and use regular
if
/else
statements instead.
when()
is a flavour of pattern matching (or an if-else abstraction) in
which a value is matched against a sequence of condition-action sets. When a
valid match/condition is found the action is executed and the result of the
action is returned.
Value
The value resulting from the action of the first valid match/condition is returned. If no matches are found, and no default is given, NULL will be returned.
Validity of the conditions are tested with isTRUE
, or equivalently
with identical(condition, TRUE)
.
In other words conditions resulting in more than one logical will never
be valid. Note that the input value is always treated as a single object,
as opposed to the ifelse
function.