python - 如何获取模块定义的所有子类（特定类的）？

Question

给定一个模块module和一个类MyClass，如何获取MyClass定义的所有子类的列表module？

Answer 1

您可以使用inspect.getmembers()。假设你有mymodule.py：

class A(object):
    pass


class B(A):
    pass


class C(A):
    pass

以下是获取所有子类的方法A：

import inspect
import mymodule
from mymodule import A

def is_subclass(o):
    return inspect.isclass(o) and issubclass(o, A)


print inspect.getmembers(mymodule, predicate=is_subclass)

或者，简而言之lambda：

print inspect.getmembers(mymodule,  
                         predicate=lambda o: inspect.isclass(o) and \
                                             issubclass(o, A))

Answer 2

我的尝试：

>>> def f(module):
...     things = [getattr(module, x) for x in dir(module)]
...     return [x for x in things if type(x) == type]
...
>>> import datetime
>>> f(datetime)
[<type 'datetime.date'>, <type 'datetime.datetime'>, <type 'datetime.time'>, <type 'datetime.timedelta'>, <type 'datetime.tzinfo'>]

Answer 3

classes = ()
for name in dir(module):
    obj = getattr(module, name)
    try:
        # obj.__mro__ raises AttributeError on non-class
        if MyClass in obj.__mro__ and obj is not MyClass:
            classes += (obj,)
        #else:
        #    print name, "is no subclass of", MyClass
    except AttributeError:
        #print name, "is no class"
        pass  # you might of course use an if hasattr(obj, '__mro__') instead

不漂亮，但有效。替代品是受欢迎的，但...

Answer 4

也许试试 pyclbr 模块——Python 类浏览器支持

http://pymotw.com/2/pyclbr/