Almost all languages are built this hash table data structure, in fact, a hash function, with the array and linked list implementation, the process there will be an array of dynamically reallocated. [ Reference ]
Hash table will generally be implemented in two forms, namely the so-called Map and Set, basically that is the only use of the Set Map Key value information, such as Java-based HashSet HashMap is achieved.
Mentioned sequence hash table may be some questions about the comparison of the various language also has its own characteristics.
To distinguish between ordered, unordered and ordered: ordered, disordered refers to the insertion element, holding the inserted sequential, i.e. the first element is inserted into the front portion of the set of priority (view it or iterate through it). And sorting means after the insertion element, the collection element is automatically sorted. (E.g., ascending order).
1, start with Python: