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Date: Thu, 08 Dec 2011 16:34:54 +0000
From: Andrea Crotti <andrea.crotti.0@gmail.com>
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Subject: adding elements to set
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:16847

I've wasted way too much time for this, which is surely not a Python bug,
not something that surprised me a lot.

I stupidly gave for granted that adding an object to a set would first
check if there are equal elements inside, and then add it.

As shown below this is not clearly the case..
Is it possible to get that behaviour implementing another magic method
in my C class or I just have use another function to check (as I'm doing
now).

class C(object):

     def __init__(self, x):
         self.x = x

     def __eq__(self, other):
         return self.x == other.x


if __name__ == '__main__':
     s = set()
     c1 = C(1)
     c2 = C(1)
     assert c1 == c2
     s.add(c1)
     s.add(c2)

     print len(s)