Binding a method to class instance on fly in Python-CodePudding

class mc:
    def show(self):
        self.func()


a = mc()
def myfunc(self):
    print('instance function')
a.func = myfunc
a.show()

The above codes do not work: TypeError: myfunc() missing 1 required positional argument: 'self'. Why the instance name is not automatically inserted by python, considering the fact that the dot notation is used?

CodePudding user response：

It can work like this, since the function isn't really an instance method

class mc:
    def show(self):
         self.x = 1
         func(self)


a = mc()
def myfunc(self):
    print (self.x)
    print('instance function')
a.func = myfunc
a.show()

CodePudding user response：

You can dynamically add a method to a class using monkey patching.

class mc:
    def show(self):
        self.func()

a = mc()
def myfunc(self):
    print('instance function')
mc.func = myfunc
a.show()