Python Collections Module
Specialized container datatypes — deque, Counter, defaultdict, namedtuple, OrderedDict. This category documents 20 Python collections module entries, and each page gives you the full syntax, the parameter list, the return value, and a runnable example. The entries include: collections.deque(), deque.append(), deque.appendleft(), deque.pop(), deque.popleft(), deque.extend(), deque.extendleft(), deque.rotate(), deque.count(), deque.clear(), collections.Counter(), Counter.most_common(), Counter.elements(), Counter.subtract(), Counter.update(), collections.defaultdict(), collections.namedtuple(), collections.OrderedDict(), OrderedDict.move_to_end(), collections.ChainMap(). collections.deque() returns a double-ended queue (deque) with efficient O(1) appends/pops from both ends. deque.append() adds x to the right side of the deque. deque.appendleft() adds x to the left side of the deque. deque.pop() removes and returns the rightmost element. Raises IndexError if empty. deque.popleft() removes and returns the leftmost element. Raises IndexError if empty. For a structured walkthrough of the whole topic, read the Collections Module guide.