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In this tutorial we will discuss about encapsulation an important part of object oriented programming

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is d encapsulation feature encapsulation is used to hide the values of these gate all or data object

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inside a class preventing unauthorized access to them.

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So encapsulation is about ensuring the safe storage of data data should be safe from changes by external

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processes the encapsulation feature involves grouping attributes

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and method into packages that contain different forms of access.

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For example certain methods an attribute are packaged as public and so these attributes and methods

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can be accessed by any class next Some attribute and method.

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Packaged as protected that means only the child classes can access these attributes and methods which

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are defined in the bad and class nixed certain attributes and methods are packaged as private which

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means the methods and attributes can only be accessed by the class itself.

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Now coming to the encapsulation feature in Python encapsulation and Python lacks strict access control

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such as private and protected attributes Python interpreter will stop us from accidentally accessing

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the attribute and the method.

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But we can intentionally do anything as long as we are aware how the language works so in Python almost

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everything about classes and objects is open open or public so we can easily inspect object Internet

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and the objects are all accessible without any restrictions everything that is defined in the base class

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is inherited and accessible from derived class and this exposes in done the implementation of an object

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let us now see an example.

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So we have the Department class which is the parent class of the superclass and we have another class

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employee which is the derived class of the class department.

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Now let us create an instance of the department class let's say the department is accounting.

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This is an instance of the department class.

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So let us access the attribute defined in this class using the instance accounting dot I.D. So here

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is the value for this attribute.

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Now we can change the value of this attribute using these instance.

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So let's give another while due to this attribute and then display the attribute using the instance.

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So we weren't able to change the value of an attribute using the instant so without interacting with

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any or the method in a class we would able to change the value of an attribute.

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And this is called breaking encapsulation and it is a bad practice for a programmer.

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Because the class are the odd maintainer can no longer validate the data that is being accessed.

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And this can cause unforeseen problems with a program that is dependent on the class it is inheriting

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from so object where tables are attributes should not always be directly accessible to prevent accidental

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change.

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The attribute can sometimes only be change using the method the methods can ensure the correct values

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are set.

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And if an incorrect value is set the method can return and error python and relies on programming conventions

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to indicate the intended use of an object.

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So instead of having to enforce language rules it is left to the programmer to observe conventions and

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these conventions are based on naming.

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So let's understand this Python doesn't have the concept of private method there are no arbitrary restrictions

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when accessing part of a class so there are no ways to impose a metered out at tribute to be strictly

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private.

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But to be able to have the encapsulation feature Python has a concept of hidden variables in which Python

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does not restrict access but hinders access to certain variables by mutilating them.

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Let us now see if you example to understand how Python uses naming convention to hinder access to attribute

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or method.

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So here we have defined a class test 1 and there is a variable defined in the init method of this class.

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So if you observe there is a leading underscored a single leading underscored before the variable name

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and when you see a variable.

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Having a single leading underscore that means we should stay away from accessing these attribute or

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methods but that does not mean that we cannot access these attributes so let us try accessing this Redburn

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underscored a using an instance of this class.

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Text one.

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So we have created an instance of the test of the class test 1 and access this attribute containing

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a single leading underscore and we were able to read the content of this variable and we can also change

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the value to which this readable are the attributes pointing to two letters.

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Go ahead and change the value of this variable and then display in Sweden.

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So even though this variable has been marked as private using a single leading underscore we were able

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to change the value of this variable externally that is from outside the class.

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Let's see another example.

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And here's another class based too.

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In this class we have the init method.

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We have defined two variables or attribute in the init method which have been marked as private using

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naming convention one attribute has a leading single underscored and the added attribute has a leading

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double underscore.

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No let us create an instance of this class and try accessing both of these attributes.

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So here we have created an instance of the class.

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Now let us try accessing the private attributes defined in this class.

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So let us first access the variable B

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so we were able to see the content of this variable by directly accessing using an instance.

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Now let us try to access the second variable double underscore D.

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Now we have an exception drawn by the interpreter and the error is an attribute error and it says test

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to object has no attribute double underscore D.

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So in order to understand this error let us call the building function.

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D I add in order to see the list of attributes for the instance test case 2.

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So here we have the attributes for the instance test case 2.

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This is the first attribute underscored b a single leading underscore before the attribute name and

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then we also have the second attribute teal.

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So if you'll notice the double underscore D attribute has been mutilated or converted by adding the

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class name before the attribute any and the interpreter does this secretly and this concept of mutilating

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the attribute name is known as name mangling.