As of Swift 2.0, you don’t need to write your own extension to filter nil values from an Array, you can use flatMap, which flattens the Array and filters nils:

let optionals : [String?] = ["a", "b", nil, "d"]
let nonOptionals = optionals.flatMap{$0}
print(nonOptionals)

Prints:

[a, b, d]

Note:

There are 2 flatMap functions:

• One flatMap is used to remove non-nil values which is shown above. Refer – https://developer.apple.com/documentation/swift/sequence/2907182-flatmap

• The other flatMap is used to concatenate results. Refer – https://developer.apple.com/documentation/swift/sequence/2905332-flatmap