你如何在Python中克隆一个类？

Question

I have a class A and i want a class B with exactly the same capabilities. I cannot or do not want to inherit from B, such as doing class B(A):pass Still i want B to be identical to A, yet have a different i: id(A) != id(B) Watch out, i am not talking about instances but classes to be cloned.

Answer 1

I'm pretty sure whatever you are trying to do can be solved in a better way, but here is something that gives you a clone of the class with a new id:

def c():
    class Clone(object):
        pass

    return Clone

c1 = c()
c2 = c()
print id(c1)
print id(c2)

gives:

4303713312
4303831072

Answer 2

I guess this is not what you wanted but its what the question seems to be asking for...

class Foo(object):
    def bar(self):
        return "BAR!"

cls = type("Bar", (object,), dict(Foo.__dict__))

print cls

x = cls()
print x.bar()

Answer 3

maybe i misunderstood you question but what about wrapping A in B?

class A:

    def foo(self):
        print "A.foo"

class B:

    def __init__(self):
        self._i = A()

    def __getattr__(self, n):
        return getattr(self._i, n)

Answer 4

You can clone the class via inheritance. Otherwise you are just passing around a reference to the class itself (rather than a reference to an instance of the class). Why would you want to duplicate the class anyway? It's obvious why you would want to create multiple instances of the class, but I can't fathom why you would want a duplicate class. Also, you could simply copy and paste with a new class name...