On Mon, Oct 12, 2009 at 3:45 PM, Peng Yu <pengyu...@gmail.com> wrote: > Hi, > > I'm wondering what is the general way to define __hash__. I could add > up all the members. But I am wondering if this would cause a > performance issue for certain classes. > > Regards, > Peng > > > #!/usr/bin/env python > > class A: > def __init__(self, a, b) : > self._a = a > self._b = b > > def __str__(self): > return 'A(%s, %s)' %(self._a, self._b) > > __repr__ = __str__ > > def __cmp__(self, other): > if self._a < other._a: > return -1 > elif self._a > other._a: > return 1 > elif self._b < other._b: > return -1 > elif self._b > other._b: > return 1 > else: > return 0 > > def __hash__(self): > return self._a + self._b > > if __name__ == '__main__': > > x = A(1, 1) > > aset = set() > aset.add(x) > print aset
What if A has a third member, which is a string? Is there a function to convert an arbitrary string to an int? -- http://mail.python.org/mailman/listinfo/python-list
