Several folk have said that objects that compare equal must hash equal,
and the docs also state this
http://docs.python.org/dev/reference/datamodel.html#object.__hash__
I'm hoping somebody can tell me what horrible thing will happen if this
isn't the case? Here's a toy example of a class I'm thinking of writing
that will compare equal with int's, but hash differently:
--> class Wierd():
... def __init__(self, value):
... self.value = value
... def __eq__(self, other):
... return self.value == other
... def __hash__(self):
... return hash((self.value + 13) ** 3)
...
--> one = Wierd(1)
--> two = Wierd(2)
--> three = Wierd(3)
--> one
<Wierd object at 0x00BFE710>
--> one == 1
True
--> one == 2
False
--> two == 2
True
--> three == 3
True
--> d = dict()
--> d[one] = '1'
--> d[two] = '2'
--> d[three] = '3'
--> d
{<Wierd object at 0x00BFE710>: '1',
<Wierd object at 0x00BFE870>: '3',
<Wierd object at 0x00BFE830>: '2'}
--> d[1] = '1.0'
--> d[2] = '2.0'
--> d[3] = '3.0'
--> d
{<Wierd object at 0x00BFE870>: '3',
1: '1.0',
2: '2.0',
3: '3.0',
<Wierd object at 0x00BFE830>: '2',
<Wierd object at 0x00BFE710>: '1'}
--> d[2]
'2.0'
--> d[two]
'2'
All information greatly appreciated!
~Ethan~
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