Inverting a dictionary when some of the original values are identical

Question

Say I have a dictionary called word_counter_dictionary that counts how many words are in the document in the form {\'word\' : number}. For example,

Answer 1

Here's a version that doesn't "invert" the dictionary:

>>> import operator
>>> A = {'a':10, 'b':843, 'c': 39, 'd': 10}
>>> B = sorted(A.iteritems(), key=operator.itemgetter(1), reverse=True)
>>> B
[('b', 843), ('c', 39), ('a', 10), ('d', 10)]

Instead, it creates a list that is sorted, highest to lowest, by value.

To get the top 25, you simply slice it: B[:25].

And here's one way to get the keys and values separated (after putting them into a list of tuples):

>>> [x[0] for x in B]
['b', 'c', 'a', 'd']
>>> [x[1] for x in B]
[843, 39, 10, 10]

or

>>> C, D = zip(*B)
>>> C
('b', 'c', 'a', 'd')
>>> D
(843, 39, 10, 10)

Note that if you only want to extract the keys or the values (and not both) you should have done so earlier. This is just examples of how to handle the tuple list.