Question

I’m still learning C# and was surprised to find out that a List<T> is much more like a std::vector than a std::list. Can someone describe all the C# collections in terms of the STL (or if STL comparisons are difficult, standard conceptual data types with Wikipedia links? I expect the reference would be widely useful.

A minimal list of collections of interest include (feel free to add others):

• Array
• List
• ArrayList
• HashTable
• Dictionary
• ListDictionary
• SortedDictionary
• SortedList
• Queue
• Stack

Edit: I just found this similar question that may be of interest: Mapping between stl C++ and C# containers

Answer 1

Here’s what I’ve found (ignoring the old non-generic collections):

• Array – C array, though the .NET Array can have a non-zero starting index.
• List<T> – std::vector<T>
• Dictionary<TKey, TValue> – unordered_map<Key, Data>
• HashSet<T> – unordered_set<Key>
• SortedDictionary<TKey, TValue> – std::map<Key, Data>
• SortedList<TKey, TValue> – equivalent to a std::vector<T> but keeping it ordered by using binary search + insert when adding elements.
• SortedSet<T> – std::set<Key>
• Queue<T> – std::queue<T>
• Stack<T> – std::stack<T>
• LinkedList<T> – std::list<T>

Notably missing from the .NET collections are the “multi-” variants, e.g., multiset, multimap, etc. However, they have added a number of very useful threadsafe collections: the “Concurrent-” variants, e.g., ConcurrentDictionary, ConcurrentQueue, etc.