Difference between Single underscore and Double underscore in python programming.

Single Underscore

In Python, a single underscore before a variable or method name is typically used to indicate that the variable or method is intended to be private, i.e.,

• It should not be accessed or modified outside of the current class or module.

Note: This is just a convention and does not actually prevent the variable or method from being accessed or modified.

class Example:
    def __init__(self):
        self._private_var = 10  # private variable
    
    def _private_method(self):
        print('This is a private method')
        
    def public_method(self):
        print('This is a public method')
        self._private_method()  # can call private method
        
e = Example()
e.public_method()  # can call public method
# Output:
# This is a public method
# This is a private method

e._private_var = 20  # can access private variable (not enforced)
print(e._private_var)  # can print private variable (not enforced)
# Output: 20

The single underscore before _private_var and _private_method is used to indicate that they are intended to be private, but they can still be accessed from outside the class, as demonstrated by the assignment and print statements.

Double Underscore

A double underscore before a variable or method name invokes name mangling in Python, which means that the name is modified to be harder to access from outside the class.

Specifically, the name is prefixed with an underscore and the name of the class in which it is defined.

• This is intended to prevent accidental name collisions between attributes of different classes.

Note: Name mangling can still be bypassed by accessing the attribute using the modified name, so it is still not a true privacy mechanism.

class Example:
    def __init__(self):
        self.__mangled_var = 20  # name-mangled variable
    
    def __mangled_method(self):
        print('This is a mangled…