Let's make a class that returns a random number for its hash.
>>> import random
>>> class DictDestroyer(object):
... def __hash__(self): return random.randint(0, 2**31)
...
>>> d = DictDestroyer()
>>> hash(d)
520880499
>>> hash(d)
793941724
Now, DictDestroyer lives up to its name:
>>> a = {d:1, d:2, d:3}
>>> import pprint
>>> pprint.pprint(a)
{<__main__.DictDestroyer object at 0x00CE8E90>: 1,
<__main__.DictDestroyer object at 0x00CE8E90>: 2,
<__main__.DictDestroyer object at 0x00CE8E90>: 3}
What is this? One key has multiple values? What happens when data is fetched?
>>> a[d]
1
>>> a[d]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
KeyError: <__main__.DictDestroyer object at 0x00CE8E90>
Inconsistent behavior. Some times it returns one of the values, other times it gives a key error.
The C source for python dictionaries holds the answer.
I'll have to update later when I figure it out.
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