On Sat, 15 Feb 2014 15:40:54 -0500, Terry Reedy wrote: > 'Identity' is an abstraction. For immutable objects, it is essentially > irrelevant. For mutable objects, it is essential in the following sense. > A and B are the same object if mutating A necessarily mutates B and > different if they can be independently mutated.
That's not quite right. See the earlier example in this thread about numpy arrays. Since mutator methods can have side-effects, and objects can act as proxies or views to other methods, we can't make any conclusion about identity from the fact that mutation affects two or more objects. [Aside: I think the numpy array API is poor, since it doesn't make clear the distinction between arrays which are being used as views to another array, and arrays which are being used as independent arrays.] -- Steven -- https://mail.python.org/mailman/listinfo/python-list
