python面向对象（七）属性方法的添加

通常情况下，当我们定义了一个class，创建了一个class的实例后，我们可以给该实例绑定任何属性和方法，这就是动态语言的灵活性。下来我就讲下添加属性和方法，同时也将下限值添加属性方法。

添加属性

给一个实例添加属性和方法时，只有对象能使用，对类添加方法和属性时，为类属性和类方法

>>> class Peopre(object):

	"""docstring for Peopre"""

	def __init__(self):

		pass

... ... ... ... ...

>>> p=Peopre()

>>> Peopre.__dict__

mappingproxy({'__module__': '__main__', '__doc__': 'docstring for Peopre', '__init__': <function Peopre.__init__ at 0x02B1B6F0>, '__dict__': <attribute '__dict__' of 'Peopre' objects>, '__weakref__': <attribute '__weakref__' of 'Peopre' objects>})

>>> p.__dict__

{}

#  -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

# 对实例添加属性

>>> p.name='张三'

>>> p.name

'张三'

>>> Peopre.__dict__

mappingproxy({'__module__': '__main__', '__doc__': 'docstring for Peopre', '__init__': <function Peopre.__init__ at 0x02B1B6F0>, '__dict__': <attribute '__dict__' of 'Peopre' objects>, '__weakref__': <attribute '__weakref__' of 'Peopre' objects>})

#  -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

# 对类添加属性，添加的为类属性

>>> Peopre.name='name'

>>> Peopre.age='12'

>>> Peopre.__dict__

mappingproxy({'__module__': '__main__', '__doc__': 'docstring for Peopre', '__init__': <function Peopre.__init__ at 0x02B1B6F0>, '__dict__': <attribute '__dict__' of 'Peopre' objects>, '__weakref__': <attribute '__weakref__' of 'Peopre' objects>, 'name': 'name', 'age': '12'})

>>> p1=Peopre()

>>> p1.name

'name'

>>> p1.age

'12'

>>> p.name

'张三'

添加方法

>>> class Peopre(object):

	"""docstring for Peopre"""

	def __init__(self):

		pass

... ... ... ...

>>> def hi():

		print("你好")

... ...

>>> Peopre.__dict__

mappingproxy({'__module__': '__main__', '__doc__': 'docstring for Peopre', '__init__': <function Peopre.__init__ at 0x0327E810>, '__dict__': <attribute '__dict__' of 'Peopre' objects>, '__weakref__': <attribute '__weakref__' of 'Peopre' objects>})

#  -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

# 添加的方法为类方法

>>> Peopre.hi=hi

>>> Peopre.__dict__

mappingproxy({'__module__': '__main__', '__doc__': 'docstring for Peopre', '__init__': <function Peopre.__init__ at 0x0327E810>, '__dict__': <attribute '__dict__' of 'Peopre' objects>, '__weakref__': <attribute '__weakref__' of 'Peopre' objects>, 'hi': <function hi at 0x0327E858>})

>>> Peopre.hi

<function hi at 0x0327E858>

>>> Peopre.hi()

你好

>>> def hello():

... 	print("hello!")

...

>>> p = Peopre()

>>> p.hi

<bound method hi of <__main__.Peopre object at 0x032722B0>>

>>> p.hi()

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

TypeError: hi() takes 0 positional arguments but 1 was given

#  -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

# 添加的为普通方法

>>> p.hello = hello

>>> p.hello()

hello!

>>> p.__dict__

{'hello': <function hello at 0x0327E8A0>}

>>>

删除属性、方法

删除的方法:

del 对象.属性名
delattr(对象, "属性名")

>>> class Peopre(object):

	"""docstring for Peopre"""

	def __init__(self, name):

		self.name = name

	def hi(self):

		print("我的名字是:%s"%self.name)

... ... ... ... ... ...

>>> p = Peopre("张三")

>>> p.hi()

我的名字是:张三

>>> p.__dict__

{'name': '张三'}

>>> del(p.name)

>>> p.__dict__

{}

#   删除方法

>>> Peopre.__dict__

mappingproxy({'__module__': '__main__', '__doc__': 'docstring for Peopre', '__init__': <function Peopre.__init__ at 0x02D2E858>, 'hi': <function Peopre.hi at 0x02D2E810>, '__dict__': <attribute '__dict__' of 'Peopre' objects>, '__weakref__': <attribute '__weakref__' of 'Peopre' objects>})

>>> def hello():

... 	print("你好")

...

>>> Peopre.hello = hello

>>> Peopre.__dict__

mappingproxy({'__module__': '__main__', '__doc__': 'docstring for Peopre', '__init__': <function Peopre.__init__ at 0x02D2E858>, 'hi': <function Peopre.hi at 0x02D2E810>, '__dict__': <attribute '__dict__' of 'Peopre' objects>, '__weakref__': <attribute '__weakref__' of 'Peopre' objects>, 'hello': <function hello at 0x0110D660>})

>>> del(Peopre.hello)

>>> Peopre.__dict__

mappingproxy({'__module__': '__main__', '__doc__': 'docstring for Peopre', '__init__': <function Peopre.__init__ at 0x02D2E858>, 'hi': <function Peopre.hi at 0x02D2E810>, '__dict__': <attribute '__dict__' of 'Peopre' objects>, '__weakref__': <attribute '__weakref__' of 'Peopre' objects>})

>>>

`slots`

限制该class能添加的属性. 但__slots__定义的属性仅对当前类起作用，对继承的子类是不起作用的.

>>> class Peopre(object):

	"""docstring for Peopre"""

	__slots__ = ("name","age")

... ... ...

>>> p = Peopre

>>> p = Peopre()

>>> p.name= "张三"

>>> p.age= 14

>>> p.height = 170

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

AttributeError: 'Peopre' object has no attribute 'height'

#   对继承的子类是不起作用的

>>> class Test(Peopre):

		pass

... ... ...

>>> t = Test()

>>> t.height = 170

>>>

巴特西

python面向对象（七）属性方法的添加

添加属性

添加方法

删除属性、方法

`slots`

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