[swift-evolution] Adding a new filter method which returns 2 arrays

[Tino Heth]

I would prefer a more general approach:
Return value could be a dictionary whose values are arrays, and the supplied function could by anything that maps target contents to possible keys (Bool would be possible, but also attributes like "lastName", "age"…).
But it isn't that hard to write this on your own, so I'm not sure if it's fundamental enough for stdlib...

Tino