On Thu, 29 Oct 2009 23:10:39 -0400, Nick Stinemates wrote: >> Some objects are singletons, ie there's only ever one of them. The most >> common singleton is None. In virtually every other case you should be >> using "==" and "!=". > > Please correct me if I am wrong, but I believe you meant to say some > objects are immutable, in which case you would be correct.
No, being immutable does not imply there is only one of it. Strings and ints are immutable: >>> a = 987654 >>> b = 987654 >>> a == b True >>> a is b False However, None, True, False, NotImplemented, and most (all?) builtin functions are singletons: >>> f = len; g = len >>> f is g True >>> x = None; y = None >>> x is y True -- Steven -- http://mail.python.org/mailman/listinfo/python-list
