Python Collections Journey | defaultdict

 The "collections" module provides specialized container datatypes providing alternatives to Python's gneeral purpose built-in containers, dict, list, set and tuple. 

An usage example : 

def groupAnagrams(strs):
    res = collections.defaultdict(list)
    for each in strs:
        res[tuple(sorted(each))].append(each)
    return res.values()


strs = ["eat", "tea", "tan", "ate", "nat", "bat"]
import collections

#print(collections.defaultdict(list))
res = groupAnagrams(strs)
print(res)

Extract from : $python_environment/Lib/collections/__init__.py

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