A view of a string’s contents as a collection of characters.
Swift Standard Library
In Swift, every string provides a view of its contents as characters. In this view, many individual characters—for example, “é”, “김”, and “🇮🇳”—can be made up of multiple Unicode code points. These code points are combined by Unicode’s boundary algorithms into extended grapheme clusters, represented by the Character type. Each element of a CharacterView collection is a Character instance.
You can convert a String.CharacterView instance back into a string using the String type’s init(_:) initializer.