The flatMap() method was useful for a variety of things in Swift 4.0, but one was particularly useful: the ability to transform each object in a collection, then remove any items that were nil.
Swift Evolution proposal SE-0187 suggested changing this, and as of Swift 4.1 this flatMap() variant has been renamed to compactMap() to make its meaning clearer.
For example:
let array = ["1", "2", "Fish"]
let numbers = array.compactMap { Int($0) }That will create an Int array containing the numbers 1 and 2, because "Fish" will fail conversion to Int, return nil, and be ignored.
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Other changes in Swift 4.1…
- Synthesized Equatable and Hashable
- Key decoding strategies for Codable
- Conditional conformances
- Recursive constraints on associated types
- Build configuration import testing
- Target environment testing
Download all Swift 4.1 changes as a playground Link to Swift 4.1 changes
