MutableVector::mapWithKey

Returns a MutableVector containing the values after an operation has been applied to each key and value in the current MutableVector

public function mapWithKey<Tu>(
  (function(int, Tv): Tu) $fn,
): MutableVector<Tu>;

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

Parameters

• (function(int, Tv): Tu) $fn - The callback containing the operation to apply to the MutableVector keys and values.

Returns

• MutableVector<Tu> - a MutableVector containing the values after a user-specified operation on the current Vector's keys and values is applied.