Cleanest way to change instance variable in class after each method runs?

Question

Say I wanted to alter an instance variable after running each method in a class. What is the best way to do this? I am aware of how to use decorators (at a very basic level), but don't know how to modify instance variables from a class using them.

As an example, I want to achieve what is shown below, but without explicitly calling post_method_routine from each method

class MyClass():
    def __init__(self):
        self.state = True

    def post_method_routine(self):
        self.state = False
        print(self.state)

    def method1(self):
        # do stuff
        self.post_method_routine()

    def method2(self):
        # do stuff
        self.post_method_routine()

    def methodN(self):
        # do stuff
        self.post_method_routine()

myinst = MyClass()
myinst.method1() # Output: False

Joran Beasley · Accepted Answer · 2019-12-24 03:58:26Z

decorators are a clean way to solve this

def post_method(fn):
    def __inner(self,*args,**kwargs):
        result = fn(*args,**kwargs)
        self.post_method_routine()
        return result
    return __inner

now just use that ... but i dont know what your really accomplishing by doing this

class MyClass():
    def __init__(self):
        self.state = True

    def post_method_routine(self):
        self.state = False
        print(self.state)

    @post_method
    def method1(self):
        # do stuff

    @post_method    
    def method2(self):
        # do stuff

if you wanted to automagically apply it to all methods that start with method you could do

class MyClass():
    def __init__(self):
        self.state = True

    def post_method_routine(self):
        self.state = False

    def method1(self):
        # do stuff

    def method2(self):
        # do stuff

for method_name in dir(MyClass):
    if method_name.startswith("method"):
        setattr(MyClass,method_name,post_method(getattr(MyClass,method_name)))

however i would strongly discourage doing this as it appears to be "magic" to the casual observer

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