How to use swift flatMap to filter out optionals from an array

Question

I\'m a little confused around flatMap (added to Swift 1.2)

Say I have an array of some optional type e.g.

let possibles:[Int?] = [nil, 1, 2, 3, nil, nil         


        

Answer 1

You could use reduce:

let flattened = possibles.reduce([Int]()) { 
        if let x = $1 { return $0 + [x] } else { return $0 } 
    }

You are still kind of declaring the type, but it's slightly less obtrusive.