Introspection mechanism
1. Definition
Introspection is to query the internal structure of the object through a certain mechanism
class Person:
"""
"""
name="User"
class Student(Person):
def __init__(self,school_name):
self.school_name = school_name
if __name__ = "__main__":
user = Student("小明")
#通过__dict__查询属性
print(user.__dict__) # {’school_name‘:’小明‘}
print(user.name) # user
print(Person.__dict__)
# {'__module__':'__main__','__name__':'__user__','__dict__':<attribute'__dict__' of 'Person' objects>,'__weakref__':<attribute'__weakref__' of 'Person' objects>,'__doc__':None}
__weakref__Refers to weak references, __doc__refers to documents, that is, in the class""" ..."""
# 赋值
user.__dict__["school_addr"] = "北京市"
print(user.school_addr) # 北京市
Two, dir function
dirThe function can list all the attributes in the object, but only the attribute name and no attribute value.
print(dir(user))
#['__class__','__delattr__','__dict__','__dir__','__doc__','__eq__','__format__','__ge__','__getattribute__','__gt__','__hash__'] 还有很多
a=[1,2]
print(a.__dict__)
#'list' object has no attribute '__dict__'
print(dir(a))
#['__add__','__class__','__contains__','__delitem__','__dir__']等等