Python OOP：创建一个是多个类的实例的对象

发布于 2025-01-24 08:45:01 字数 1077 浏览 0 评论 0原文

假设我构建了一些包含一些实例方法的类：

class A:
    def func_of_A(self):
        print("foo")

class B:
    def func_of_B(self):
        print("bar")

如何构造对象/变量c，这是a和b的实例代码> ，以便我可以调用c.func_of_a（）和c.func_of_b（）？

我当然可以构建一个新的类，该类从A和b和Make c一个成员：

class C(A,B):
    pass

c = C()

但这不是我正在寻找的成员为了。每当我计划使用已经建造的组合时，我宁愿不会创建一个新课程。

我还可以创建一个函数来动态定义新类并返回一个实例：

def merge(*inherit_from):
    class D(*inherit_from):
        pass
    return D()

c = merge(A,B)

但是这是无法诅咒的，因为现在MERGE（a，b），merge（a）和MERGE（B）全部返回相同的类型＆lt; class'__ -Main __. Merge。＆lt; locals＆gt; .d'＆gt;。

应该有一种预期的方法来做到这一点，不应该吗？

是否有一个解决方案可以很好地扩展到涉及的类数量？如果我已经有类A1，类A2，...，类A100，我想构造一些c成为A2类，A23类，A72类，A99类的实例，但我该怎么办？考虑到〜2^100组合，为每种组合创建一个新课程几乎是不可能的。

原文

Say I built some classes containing some instance methods:

class A:
    def func_of_A(self):
        print("foo")

class B:
    def func_of_B(self):
        print("bar")

How can I construct an object/variable c that is an instance of both A and B, so that I can call both c.func_of_A() and c.func_of_B()?

I could of course build a new class inheriting from A and B and make c a member of that:

class C(A,B):
    pass

c = C()

But that is not what I am looking for. I would rather not create a new class every time I am planning to use a combination of already built ones.

I could also create a function to dynamically define a new class and return an instance of it:

def merge(*inherit_from):
    class D(*inherit_from):
        pass
    return D()

c = merge(A,B)

but this is beyond cursed, because now merge(A,B), merge(A) and merge(B) all return the same type <class '__main__.merge.<locals>.D'>.

There should be an intended way to do this, shouldn't?

Is there a solution that scales well with the number of classes involved? If I already have class A1, class A2, ..., class A100 and I want to construct some c to be an instance of class A2, class A23, class A72, class A99 but not the others how would I do that? Creating a new class for every combination is pretty much impossible, given the ~2^100 combinations.

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樱花坊 2025-01-31 08:45:01

您可以使用type（），如@deceze所述

>>> class A:
...     def a():
...         pass
... 
>>> class B:
...     def b():
...         pass
... 
>>> def merge(name: str, *parents):
...     return type(name, parents, dict())
... 
>>> C = merge("C", A, B)
>>> C.a()
>>> C.b()
>>>

You can use type() for that as @deceze mentioned

>>> class A:
...     def a():
...         pass
... 
>>> class B:
...     def b():
...         pass
... 
>>> def merge(name: str, *parents):
...     return type(name, parents, dict())
... 
>>> C = merge("C", A, B)
>>> C.a()
>>> C.b()
>>>

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