MutableSet::mapWithKey

Returns a MutableSet containing the values after an operation has been applied to each "key" and value in the current Set.

Description

public function mapWithKey(
  callable $fn,
): MutableSet<Tu>

Returns a MutableSet containing the values after an operation has been applied to each "key" and value in the current Set.

Since sets don't have keys, the callback uses the values as the keys as well.

Every value in the current MutableSet is affected by a call to mapWithKey(), unlike filterWithKey() where only values that meet a certain criteria are affected.

Parameters

  • callable $fn - The callback containing the operation to apply to the current MutableSet "keys" and values.

Return Values