Peter Otten wrote:
Ethan Furman wrote:
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)
...
Try this:
d = {Wierd(1): 0}
1 in d
False
1 in d.keys()
True
My apologies -- I'm trying this in Python3:
--> two in d
True
--> two in d.keys()
True
-->
--> 2 in d
True
--> 2 in d.keys()
True
~Ethan~
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