python __dict__ 跟 dir()的区别

Posted 2022-05-29 tangkaishou

__dict__:要是对象的话返回的是一个对象自身的实例属性、不包括类的属性；要是类的__dict__则不包括父类的属性，只包含自身类属性【方法、类变量】，不包括实例属性。正是这样、每个实例的实例属性才会互不影响。

dir():返回的是对象的所有属性、包括父类的属性

 

python一切皆对象、类本身也有__dict__函数、跟dir()函数、那么类与实例的两个函数有没有区别呢？

答案是:有的

class A():
    Tang = "tang"
    def __init__(self):
        self.model = None
        self.setModel()

    def setModel(self):
        self.model = "tanglaoer"

class B(A):
    BLao = "BLao"
    def __init__(self):
        self.model = "hello world"
        super().__init__()


b = B()
print(b.__dict__)
print(B.__dict__)
print(A.__dict__)
print(dir(b))
print(dir(B))
print(dir(A))

打印结果

‘model‘: ‘tanglaoer‘
‘__module__‘: ‘__main__‘, ‘BLao‘: ‘BLao‘, ‘__init__‘: <function B.__init__ at 0x1053c1378>, ‘__doc__‘: None
‘__module__‘: ‘__main__‘, ‘Tang‘: ‘tang‘, ‘__init__‘: <function A.__init__ at 0x1053c1488>, ‘setModel‘: <function A.setModel at 0x1053c1510>, ‘__dict__‘: <attribute ‘__dict__‘ of ‘A‘ objects>, ‘__weakref__‘: <attribute ‘__weakref__‘ of ‘A‘ objects>, ‘__doc__‘: None
[‘BLao‘, ‘Tang‘, ‘__class__‘, ‘__delattr__‘, ‘__dict__‘, ‘__dir__‘, ‘__doc__‘, ‘__eq__‘, ‘__format__‘, ‘__ge__‘, ‘__getattribute__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__init_subclass__‘, ‘__le__‘, ‘__lt__‘, ‘__module__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__setattr__‘, ‘__sizeof__‘, ‘__str__‘, ‘__subclasshook__‘, ‘__weakref__‘, ‘model‘, ‘setModel‘]
[‘BLao‘, ‘Tang‘, ‘__class__‘, ‘__delattr__‘, ‘__dict__‘, ‘__dir__‘, ‘__doc__‘, ‘__eq__‘, ‘__format__‘, ‘__ge__‘, ‘__getattribute__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__init_subclass__‘, ‘__le__‘, ‘__lt__‘, ‘__module__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__setattr__‘, ‘__sizeof__‘, ‘__str__‘, ‘__subclasshook__‘, ‘__weakref__‘, ‘setModel‘]
[‘Tang‘, ‘__class__‘, ‘__delattr__‘, ‘__dict__‘, ‘__dir__‘, ‘__doc__‘, ‘__eq__‘, ‘__format__‘, ‘__ge__‘, ‘__getattribute__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__init_subclass__‘, ‘__le__‘, ‘__lt__‘, ‘__module__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__setattr__‘, ‘__sizeof__‘, ‘__str__‘, ‘__subclasshook__‘, ‘__weakref__‘, ‘setModel‘]