Python內置函數(45)——object

英文文檔：

class object
Return a new featureless object. object is a base for all classes. It has the methods that are common to all instances of Python classes. This function does not accept any arguments.
Note：object does not have a __dict__, so you can’t assign arbitrary attributes to an instance of the object class.

 

 說明：

　　1. object類是Python中所有類的基類，如果定義一個類時沒有指定繼承哪個類，則默認繼承object類。

>>> class A:
    pass

>>> issubclass(A,object)
True

　　2. object類定義了所有類的一些公共方法。

>>> dir(object)
['__class__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__le__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__']

　　3. object類沒有定義 __dict__，所以不能對object類實例對象嘗試設置屬性值。

>>> a = object()
>>> a.name = 'kim' # 不能設置屬性
Traceback (most recent call last):
  File "<pyshell#9>", line 1, in <module>
    a.name = 'kim'
AttributeError: 'object' object has no attribute 'name'

#定義一個類A
>>> class A:
    pass

>>> a = A()
>>> 
>>> a.name = 'kim' # 能設置屬性