Thank you for the comments, Fredrik Lundh. >(that's (mostly) CPython-dependent, and should be avoided)<
Then a non CPython-dependent way of doing it can be even more useful. >sure looks like four possible outcomes.< Right (but to me four explicit answers seem better than three answers and an exception still). >id(a)< I think in Python it can be something more like (but it's of little use): def identity(x): return x Or: identity = lambda x: x >(cloning is usually a sign of a design problem in python. if you think you need it, you probably don't. if you really think you need it, import copy.)< I agree (importing a module is worse than using a standard copy method, but I think this can be seen as a way to discourage the use of copy in Python). >if you can define the semantics, it's a few lines of code. if you're not sure about the semantics, a built-in won't help you...< I think the language needs a fast built-in version of it. If something is both inside Mathematica and Ruby, then probably it can be useful in Python too :-) Bye and thank you, bearophile -- http://mail.python.org/mailman/listinfo/python-list
