Scala: How to avoid check instance and casting -

i found myself in condition of running:

somecollection.filter(_.isinstanceof[foo]).asinstanceof[list[foo]]

just check if collection has instances of foo , casting final filtered collection.

is there better way (assuming cannot change current data structure)?

i tried with:

somecollection.map(case c: foo => c)

but @ runtime returns matchingerror of course looking remaining cases (case _ =>).

somecollection.collect { case c: foo => c }

Living