How can I increase counter properties of class when a instance is called?

Question

There is simple class:

class A(object):

    __COUNTER = 0

    def do_something_1(self):
        ...

    def do_something_2(self):
        ...         


        

Answer 1

Here's the simple version: How to increment a class-wide counter every time a particular function is called. The function can be __init__, which covers your specific question.

class cls(object):
    counter = 0

    def __init__(self):
        self.__class__.counter += 1
        print self.__class__.counter

a = cls()  # Prints 1
b = cls()  # Prints 2

As you can see, the trick is to increment self.__class__.counter, not self.counter. You can do that inside any member function.

But don't use names starting with a double underscore, because they have special meaning for python (unless you know and want the special meaning, of course). If you want to flag the counter as private, use a single underscore: _counter.