Define Private Methods/Functions in Python Class.

Python is very powerful and famous language, which allow us to write code as per object orientated programming (OOP) concepts. Encapsulation is one of the fundamental concepts in OOP. In encapsulation, we can wrap data and method in one unit and also restrict them to access from outside class.

As other Object Oriented Programming languages, Python also allow us to define private methods and variables.

Private Methods/Functions:

In Python, private methods can be defined as prefix function with double underscore (__) as following.

def __function_name(self)


If you try to access private method directly, it will raise exception but if you can access private method by calling it in a public method, as following.

def call_private_method(self):
	return self.__function_name()

Name mangling:

Here is another way to call private method that python allowing called name mangling. It means, any identifier starting with double underscore (__) or at most one trailing underscore is replaced with the _classname__private_function_name, where classname is the current class name with leading underscore(s) stripped. Following is the example.

obj = Classname()
obj._Classname__private_function()

Above method to call private method will show you the output of the private function instead of raising exception.

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