In Python, we can define private variables and methods. These variables and methods cannot be accessed out of the class or by the inherited class according to the Object-Oriented Paradigm. Things are a bit different in Python.
In python, we can achieve this by using Name Mangling which means adding __ before the variable or method name, let see how
class PPrint:
def __init__(self):
self.__secret_msg = 'I am alive' # This is a private variable
self.check = False
def __private_method(self): # This is a private method
print('I am private method !')
def public_method(self): # This public method, which can access the private method
self.__private_method()
def public_print(self):
print(self.__secret_msg)
print(self.check)
In the above class, we define the private methods and variables. Let see how to use them
>>> p = PPrint()
>>> p.public_print()
I am alive
False
>>> p.public_method()
I am private method !
# so far so good, let see what happends when we try to access these private methods or variables.
>>> p.__private_msg
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'PPrint' object has no attribute '__private_msg'
>>> p.__private_method()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'PPrint' object has no attribute '__private_method'
As you can see python does not allow access to these private variables and methods. But, If I say you can access these private variables and methods.
>>> dir(p)
['_PPrint__private_method', '_PPrint__secret_msg', '__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'check', 'public_method', 'public_print']
# You can see we have private method and variable '_PPrint__private_method', '_PPrint__secret_msg'
>>> p._PPrint__private_method()
I am private method !
>>> p._PPrint__secret_msg
'I am alive'
So, that's what Name Mangling do it add *<classname>_<method/variablename>.
Conclusion
In Python, we can use the name mangling to define the private method and variables, but it not as strict as in other OOP languages. It's almost like a convention which is followed by all python developer. You may also found _ added before the method and variable name, which is just another way to say don't access these methods directly.
Cheers!
#100DaysToOffload #Python
