En Mon, 17 Nov 2008 22:04:43 -0200, Mr.SpOOn <[EMAIL PROTECTED]>
escribió:
On Mon, Nov 17, 2008 at 8:30 PM, Terry Reedy <[EMAIL PROTECTED]> wrote:
Sets and dicts use __hash__ and __eq__ together, as documented.
"If a class does not define an __eq__() method it should not define a
__hash__() operation either;" (3.0 manual, but same earlier).
Well, maybe, but in the docs, for the __hash__ method I read:
"If a class does not define a __cmp__() method it should not define a
__hash__() operation either;"
From here: http://www.python.org/doc/2.5.2/ref/customization.html
Yes, __cmp__ is gone in 3.0
You said you wrote __cmp__ the same as __eq__ and that's wrong, they
return different results. Try something like this (untested):
class X:
def __init__(self, a): self.a = a
def __cmp__(self, other): return cmp(self.a, other.a)
def __hash__(self): return hash(self.a)
x1 = X(1)
x2 = X(2)
x3 = X(3)
x4 = X(1)
print len(set([x1, x2, x3, x4]) # should be 3!
--
Gabriel Genellina
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