Classes in Python

There are loads of content and age old story telling way of explain classes , I take it the nerdy way and explain on the technical part of it , in this post .

Defining a class

class ClassName:

{statement-1}

.

.

.

{statement-N}

The statements can be simple statements or it can be methods .Normally the contain methods.

Class Objects:

These supports ===> attribute references and instantiation

To understand , those two lets consider a simple class definition :

class YouNity:

"My first class"

bond = 007

def hi(self):

return 'hello world'

Attribute reference ==> YouNity.bond or YouNity.hi()

Instantiation ===> all = YouNity () , creates a new instance of the class and assigns this object to the local variable all .Hence , we can access varibales and methods of the class , as all.bond or all.hi()

__init__() ans self

This method is very much similar to the Java constructor , lets see how it can be used ?!

>>> class Who:

... def __init__(self, first, last):

... self.firstName = first

... self.lastName = last

...

>>> name = Who("hemanth", "hm")

>>> name.first,name.last

(hemanth,hm)

In the above example , the __init__ method is called when the class is instantiated , the first argument to the method is called "self" , the name self has absolutely no special meaning to Python , but can be understood as the current variables reference.

Inheritance

The child must follow the parent class , that is Derived followed by Base class in the declaration.

class DerivedClassName(BaseClassName):

{statement-1}

.

.

.

{statement-N}

If the Base is in some other package then ?

class DerivedClassName(modname.BaseClassName):

Multiple parents to a single child !!!

class DerivedClassName(Base1, Base2, Base3):

{statement-1}

.

.

.

{statement-N}

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