Python collections module: Counter, defaultdict, deque, namedtuple, ChainMap, custom containers, heapq, and LRU cache examples
This article introduces several useful classes from Python's collections module—including Counter, defaultdict, deque, namedtuple, ChainMap, UserList/UserDict/UserString, as well as heapq and an OrderedDict‑based LRU cache—explaining their purposes and providing ready‑to‑run code examples for each.