Alex Martelli wrote: > Steve Holden <[EMAIL PROTECTED]> wrote: > ... > >>>3. If two objects are equal with "==", does that >>> mean their values are the same? >> >>Almost universally, yes, although if you know enough about how the >>interpreter works "under the hood" you can define the response of >>instances of your own classes to the "==" operator (by defining their >>__eq__ method), and even define a class whose instances aren't equal to >>anything, even to themselves! > > > Hmmm... now this may be just be, but I'm quite vary of saying that, > since 1 == 1.0 == 1.0+0j, those three objects's values "are the same". > > "Are equal", sure. But I intuitively see "being the same" as a stronger > condition than "being equal". > > In mathematics, 1 is not "the same" as 1.0 -- there exists a natural > morphism of integers into reals that _maps_ 1 to 1.0, but they're still > NOT "the same" thing. And similarly for the real-vs-complex case. > > Python may differ -- try using those "equal but not the same numbers" as > keys into the same dict, and see. One of the few *surprises* I ever got > from Python...!-) > > ((I don't think this violates the "introduce no complexity that doesn't > help understanding" rule -- I think the 1==1.0 case is important!)) > > Whether it violates the rule or not it's a welcome addition, as was Bengt's.
I just wish Mike Meyer and Steven D'Aprano were close enough that you could bang their heads together. In the same playground, perhaps? :-) regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC www.holdenweb.com PyCon TX 2006 www.python.org/pycon/ -- http://mail.python.org/mailman/listinfo/python-list
