如何獲取模塊定義的所有子類（特定類）？

Question

給定一個模塊module和類MyClass，如何獲得module中定義的MyClass的所有子類的列表？

Answer 1

您可以使用inspect.getmembers()。假設你有mymodule.py：

class A(object): 
    pass 


class B(A): 
    pass 


class C(A): 
    pass 

這裏是你如何能得到的A所有子類：

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) 

，或者在短期lambda形式：

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

Answer 2

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，但工程。儘管替代品是受歡迎的...

Answer 3

我嘗試：

>>> 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 4

也許嘗試pyclbr模塊 - Python類瀏覽器支持

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