Encapsulation is one of the fundamental concepts in object-oriented programming (OOP). It describes the idea of wrapping data and the methods that work on data within one unit. This puts restrictions on accessing variables and methods directly and can prevent the accidental modification of data. To prevent accidental change, an object’s variable can only be changed by an object’s method. Those types of variables are known as private variables.
Example:
# Python program to
# demonstrate protected members
# Creating a base class
class Base:
def __init__(self):
# Protected member
self._a = 2
# Creating a derived class
class Derived(Base):
def __init__(self):
# Calling constructor of
# Base class
Base.__init__(self)
print("Calling protected member of base class: ",
self._a)
# Modify the protected variable:
self._a = 3
print("Calling modified protected member outside class: ",
self._a)
obj1 = Derived()
obj2 = Base()
# Calling protected member
# Can be accessed but should not be done due to convention
print("Accessing protected member of obj1: ", obj1._a)
# Accessing the protected variable outside
print("Accessing protected member of obj2: ", obj2._a)
Output:
Calling protected member of base class: 2
Calling modified protected member outside class: 3
Accessing protected member of obj1: 3
Accessing protected member of obj2: 2