#查看object类是否定义了'__dict__'
>>> a = dir(object)
>>> a
['__class__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__',
 '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', 
'__init_subclass__', '__le__', '__lt__', '__ne__', '__new__', '__reduce__',
 '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__',
 '__subclasshook__']
>>> '__dict__' in a
False
###################################################################################
#查看object在没有定义__dict__的情况下能否设置属性值
a = object()
a.num = 1
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
AttributeError: 'object' object has no attribute 'num'

#查看设置__dict__之后能否设置属性值
class Object(object):
    def __dict__():
        return None
>>> a = Object()
>>> a.num = 1

#!/usr/bin/python
# -*- coding: utf-8 -*-
class A(object):
    class_var = 1
    def __init__(self):
        self.name = 'xy'
        self.age = 2

    @property
    def num(self):
        return self.age + 10

    def fun(self):pass
    def static_f():pass
    def class_f(cls):pass

if __name__ == '__main__':#主程序
    a = A()
    print a.__dict__   #{'age': 2, 'name': 'xy'}   实例中的__dict__属性
    print A.__dict__   
    '''
    类A的__dict__属性
    {
    '__dict__': <attribute '__dict__' of 'A' objects>, #这里如果想深究的话查看参考链接5
    '__module__': '__main__',               #所处模块
    'num': <property object>,               #特性对象 
    'class_f': <function class_f>,          #类方法
    'static_f': <function static_f>,        #静态方法
    'class_var': 1, 'fun': <function fun >, #类变量
    '__weakref__': <attribute '__weakref__' of 'A' objects>, 
    '__doc__': None,                        #class说明字符串
    '__init__': <function __init__ at 0x0000000003451AC8>}
    '''

    a.level1 = 3
    a.fun = lambda :x
    print a.__dict__  #{'level1': 3, 'age': 2, 'name': 'xy','fun': <function <lambda> at 0x>}
    print A.__dict__  #与上述结果相同

    A.level2 = 4
    print a.__dict__  #{'level1': 3, 'age': 2, 'name': 'xy'}
    print A.__dict__  #增加了level2属性

    print object.__dict__
    '''
    {'__setattr__': <slot wrapper '__setattr__' of 'object' objects>, 
    '__reduce_ex__': <method '__reduce_ex__' of 'object' objects>, 
    '__new__': <built-in method __new__ of type object at>, 
    等.....
    '''

print dir(A)
'''
['__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'age', 'class_f', 'class_var', 'fun', 'level1', 'level2', 'name', 'num', 'static_f']
'''
a_dict = a.__dict__.keys()
A_dict = A.__dict__.keys()
object_dict = object.__dict__.keys()
print a_dict  
print A_dict  
print object_dict 
'''
['fun', 'level1', 'age', 'name']

['__module__', 'level2', 'num', 'static_f', '__dict__', '__weakref__', '__init__', 'class_f', 'class_var', 'fun', '__doc__']

['__setattr__', '__reduce_ex__', '__new__', '__reduce__', '__str__', '__format__', '__getattribute__', '__class__', '__delattr__', '__subclasshook__', '__repr__', '__hash__', '__sizeof__', '__doc__', '__init__']
'''

#因为每个类都有一个__doc__属性，所以需要去重，去重后然后比较
print set(dir(a)) == set(a_dict + A_dict + object_dict)  #True