Quick takeaways

I covered a lot of stuff in a just a few pages on collection types in Swift 3. Here are the highlights to keep in mind about the collections and indices.

• Collection types (built-in and custom) implement the Collection protocol.

• Iterating over collections has moved to the Collection - the index no longer has that ability.

• You can create your own collections by adopting the Collection protocol. You need to implement:

  • startIndex and endIndex properties,

  • The subscript method to support access to your elements

  • And the index(after: ) method to facilitate traversing your collection's indices.