Hi Greg, On Wed, Mar 29, 2006 at 12:38:55PM +1200, Greg Ewing wrote: > I'm really thinking more about the non-inplace operators. > If nb_add and sq_concat are collapsed into a single slot, > it seems to me that if you do > > a = [1, 2, 3] > b = array([4, 5, 6]) > c = a + b > > then a will be asked "Please add yourself to b", and a > will say "Okay, I know how to do that!" and promptly > concatenate itself with b.
No: there is a difference between + and += for lists. You can only concatenate exactly a list to a list. Indeed: >>> [].__add__((2, 3)) TypeError: can only concatenate list (not "tuple") to list By contrast, list += is like extend() and accepts any iterable. So if we provide a complete fix, [].__add__(x) will be modified to return NotImplemented instead of raising TypeError if x is not a list, and then [1,2,3]+array([4,5,6]) will fall back to array.__radd__() as before. I'll try harder to see if there is a reasonable example whose behavior would change... A bientot, Armin _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
