Collections are standard and general purpose data structures provided
by the standard library (i.e.: std). We already have seen the
Vec structure. All other collections of the standard library are
part of the std::collections module. They may be classified
according to their underlying structure:
Array-like structure:
Vec,VecDeque.List-like structure:
LinkedList.Tree-like structure:
BTreeSet,BTreeMap,BinaryHeap.Hash table structure:
HashSet,HashMap.
In Module collections is a guide to help choosing the right collection.