In [26]: import collections

In [27]: words = ["a","a","b","d","a"]

In [28]: cnt = collections.Counter(words)

In [29]: cnt.most_common(3)
Out[29]: [('a', 3), ('b', 1), ('d', 1)]

In [30]: cnt2 = collections.Counter('abcdfff')

In [31]: cnt + cnt2
Out[31]: Counter({'a': 4, 'b': 2, 'c': 1, 'd': 2, 'f': 3})

In [32]: d = dict([('a',1),('b',2),('c',3)])

In [33]: d
Out[33]: {'a': 1, 'b': 2, 'c': 3}

In [38]: d = collections.OrderedDict([('a',1),('b',2),('c',3)])

In [39]: for k,v in d.items():
    ...:     print(k,v)
    ...:
('a', 1)
('b', 2)
('c', 3)

In [40]: User = collections.namedtuple("User",'name age location phone')

In [41]: user = User("li",12,"wuhan","000999")

In [42]: user.age
Out[42]: 12

In [43]: user.phone
Out[43]: '000999'