>>> import collections

>>> # Tally occurrences of words in a list

>>> cnt = collections.Counter()

>>> for word in ['red', 'blue', 'red', 'green', 'blue', 'blue']:

...     cnt[word] += 1

>>> cnt

Counter({'blue': 3, 'red': 2, 'green': 1})

>>> c = collections.Counter('helloworld')

>>> c

Counter({'l': 3, 'o': 2, 'e': 1, 'd': 1, 'h': 1, 'r': 1, 'w': 1})

>>> c.most_common(3)

[('l', 3), ('o', 2), ('e', 1)]