Python: Do something for any method of a class?

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自闭症患者
自闭症患者 2021-02-19 03:01

Say I have a class with a bunch of methods:

class Human():

  def eat():
    print(\"eating\")

  def sleep():
    print(\"sleeping\")

  def throne():
    print         


        
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3条回答
  • 2021-02-19 03:19

    If you can't change how you call your methods you can use the __getattribute__ magic method (methods are attributes too remember!) you just have to be careful to check the type of attributes so you don't print "I am:" every time you want to access any string or int attributes you may have:

    class Human(object):
        def __getattribute__(self, attr):
            method = object.__getattribute__(self, attr)
            if not method:
                raise Exception("Method %s not implemented" % attr)
            if callable(method):
                 print "I am:"
            return method
    
        def eat(self):
            print "eating"
    
        def sleep(self):
           print "sleeping"
    
        def throne(self):
            print "on the throne"
    
    John = Human()
    John.eat()
    John.sleep()
    John.throne()
    

    Outputs:

    I am:
    eating
    I am:
    sleeping
    I am:
    on the throne
    
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  • 2021-02-19 03:21

    If you want to have arguments as well, you can try using metaprogramming to alter the class methods themselves to run a pre/post operation, like the answer to How to run a method before/after all class function calls with arguments passed?

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  • 2021-02-19 03:35

    You can do this if you don't mind adding an __init__ and __call__ method to your class and self to your method's arguments.

    class Human():
        def __init__(self):
            return None
        def __call__(self, act):
            print "I am:"
            method = getattr(self, act)
            if not method:
                raise Exception("Method %s not implemented" % method_name)
            method()
    
        def eat(self):
            print "eating"
    
        def sleep(self):
            print "sleeping"
    
        def throne(self):
            print "on the throne"
    
    John = Human()
    John("eat")
    John("sleep")
    John("throne")
    

    EDIT: see my other answer for a better solution

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