Learning Python

The collections module

When Python general purpose built-in containers (tuple, list, set, and dict) aren't enough, we can find specialized container data types in the collections module. They are:

Data type	Description
namedtuple()	A factory function for creating tuple subclasses with named fields
deque	A list-like container with fast appends and pops on either end
ChainMap	A dict-like class for creating a single view of multiple mappings
Counter	A dict subclass for counting hashable objects
OrderedDict	A dict subclass that remembers the order entries were added
defaultdict	A dict subclass that calls a factory function to supply missing values
UserDict	A wrapper around dictionary objects for easier dict subclassing ...