# Collection A sequence whose elements can be traversed multiple times, nondestructively, and accessed by an indexed subscript. ``` protocol Collection : Sequence ``` ## Overview Collections are used extensively throughout the standard library. When you use arrays, dictionaries, and other collections, you benefit from the operations that the `Collection` protocol declares and implements. In addition to the operations that collections inherit from the `Sequence` protocol, you gain access to methods that depend on accessing an element at a specific position in a collection. For example, if you want to print only the first word in a string, you can search for the index of the first space, and then create a substring up to that position. ``` let text = "Buffalo buffalo buffalo buffalo." if let firstSpace = text.firstIndex(of: " ") { print(text[..