The existing Person classes are as follows

class Person:

    name = 'Xiao Bai'

    def hobby(self):
        print('coding')

__Use of dict

Function: view properties in objects and view properties and methods in classes

per = Person()
print(per.__dict__)
print(Person.__dict__)

The results are as follows:

{'age': 20}
{'__module__': '__main__', 'name': 'Xiao Bai', '__init__': <function Person.__init__ at 0x00000224A9B730D0>, 'hobby': <function Person.hobby at 0x00000224A9B73158>, '__dict__': <attribute '__dict__' of 'Person' objects>, '__weakref__': <attribute '__weakref__' of 'Person' objects>, '__doc__': None}

In per object, there is only age attribute, no name attribute and hobby method.

Use of dir()

Function: view properties and methods in objects and classes

per = Person(20)
print(dir(per))
print(dir(Person))

The results are as follows:

['__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__', 'age', 'hobby', 'name']
['__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__', 'hobby', 'name']

__Use of class

Role: view class

per = Person(20)
print(per.__class__)

Execution result:

<class '__main__.Person'>

The use of setattr and getattr

setattr function: add attributes to objects
getattr function: view the corresponding properties in the object

per = Person(20)
setattr(per,'facevalue',90)
print(getattr(per,'facevalue'))
print(per.__dict__)

Execution result:

90
{'age': 20, 'facevalue': 90}

__Use of delattr_uuuu

Function: delete the corresponding attribute in the object

per = Person(20)
per.sex = 'men'
print(per.__dict__)
per.__delattr__('sex')
print(per.__dict__)

Execution result:

{'age': 20, 'sex': 'men'}
{'age': 20}