A flattened view of a base collection of collections.
- Xcode 7.0+
- Swift Standard Library
The elements of this view are a concatenation of the elements of each collection in the base.
joined method is always lazy, but does not implicitly confer laziness on algorithms applied to its result. In other words, for ordinary collections
cdoes not create new storage
cmaps eagerly and returns a new array
cmaps lazily and returns a