继承之super

Posted 2020-11-27 meloncodezhang

super（）方法：调用父类方法，也就是新建一个super类的实例对象

class super(object):
    """
    super() -> same as super(__class__, <first argument>)
    super(type) -> unbound super object
    super(type, obj) -> bound super object; requires isinstance(obj, type)
    super(type, type2) -> bound super object; requires issubclass(type2, type)
    Typical use to call a cooperative superclass method:
    class C(B):
        def meth(self, arg):
            super().meth(arg)
    This works for class methods too:
    class C(B):
        @classmethod
        def cmeth(cls, arg):
            super().cmeth(arg)
    """
    def __getattribute__(self, *args, **kwargs): # real signature unknown
        """ Return getattr(self, name). """
        pass

    def __get__(self, *args, **kwargs): # real signature unknown
        """ Return an attribute of instance, which is of type owner. """
        pass

    def __init__(self, type1=None, type2=None): # known special case of super.__init__
        """
        super() -> same as super(__class__, <first argument>)
        super(type) -> unbound super object
        super(type, obj) -> bound super object; requires isinstance(obj, type)
        super(type, type2) -> bound super object; requires issubclass(type2, type)
        Typical use to call a cooperative superclass method:
        class C(B):
            def meth(self, arg):
                super().meth(arg)
        This works for class methods too:
        class C(B):
            @classmethod
            def cmeth(cls, arg):
                super().cmeth(arg)
        
        # (copied from class doc)
        """
        pass

    @staticmethod # known case of __new__
    def __new__(*args, **kwargs): # real signature unknown
        """ Create and return a new object.  See help(type) for accurate signature. """
        pass

    def __repr__(self, *args, **kwargs): # real signature unknown
        """ Return repr(self). """
        pass

    __self_class__ = property(lambda self: type(object))
    """the type of the instance invoking super(); may be None

    :type: type
    """

    __self__ = property(lambda self: type(object))
    """the instance invoking super(); may be None

    :type: type
    """

    __thisclass__ = property(lambda self: type(object))
    """the class invoking super()

    :type: type
    """

举例

class A(object):

    def A_method(self,p1):
        print(p1)


class B(A):

    def B_method(self):
        # python3 写法
        super().A_method(10) 
        # python2 写法
        # super(B,self).A_method(10)

b = B()
b.B_method()

# 结果
10

 

使用场景，封装flask的app，供外界使用

# application.py

from flask import Flask
from flask_sqlalchemy import SQLALlchemy
class Application(Flask):
    def __init__(self,import_name):
        super(Application,self).__init__(import_name)  # python2的写法，创建Application的实例时候，传入__name__，就相当于在当前文件创建了app=Flask(__name__)实例
　　　　 # 上面的super这一行执行完成之后，self已经变成了app 
        self.config.from_pyfile("config/base_setting.py")
        db.init_app(self)

db = SQLALlchemy()

app = Application(__name__)   # 外界任何位置想使用app和db的时候，直接 from application import app,db 就可以直接使用app,db

 

 

 

 

# TOTO