Classes and Objects in Python | OOP in Python | Python for Beginners #lec85

Summary

This Python programming tutorial focuses on Object-Oriented Programming (OOP), emphasizing the importance of classes and objects. It explains the drawbacks of procedural programming and how OOP simplifies complex projects. The video uses a YouTube channel analogy to illustrate classes as blueprints for creating objects. It discusses attributes and methods, differentiating them from variables and functions. The instructor clarifies that everything in Python is an object, and classes are necessary for defining custom data types. The video concludes with a practical demonstration of creating a class and objects, and assigns an exercise to create a 'CarDesign' class with two objects.

Takeaways

• 📚 Object-Oriented Programming (OOP) is preferred over the Procedure-Oriented Programming (POP) approach, especially for handling large real-world projects.
• 🏗 A class in Python serves as a blueprint for creating objects, which are instances of the class.
• 👤 Objects have attributes (data) and methods (functions) attached to them, distinguishing them from simple variables and functions.
• 🎥 The instructor uses a virtual YouTube channel example to explain how classes and objects model real-world entities.
• 💻 Everything in Python is an object, including basic data types like integers and strings.
• 📝 The class design is like a prototype, similar to an idli maker, which simplifies object creation just as an idli maker helps make idlis efficiently.
• 🚗 A class can create many objects, like a car blueprint that helps produce multiple cars efficiently.
• 🛠 The class keyword is used to define a class, and PascalCase is recommended for naming class names.
• 🆕 Objects are created by calling the class as a constructor, and the `pass` statement can be used as a placeholder when defining empty classes.
• 📦 Classes can be thought of as user-defined data types, and objects as instances of those types, helping to manage real-world complexity in programs.

Q & A

What is the main focus of the video script?

The main focus of the video is to discuss object-oriented programming (OOP) in Python, particularly about classes and objects, how to create them, and why they are important.

What are the drawbacks of the procedure-oriented programming (POP) approach?

Procedure-oriented programming (POP) struggles to model real-world problems and cannot efficiently handle large, complex projects. This is why OOP is used in industries for large-scale software development.

What analogy does the speaker use to explain the concept of a class?

The speaker uses an 'idli maker' analogy, where the idli maker is the class (blueprint) and the idlis produced are the objects (instances). This analogy helps explain how a class is like a design for creating objects.

What is the purpose of a class in OOP?

A class in OOP serves as a blueprint or design for creating objects. It allows developers to define attributes and methods, making it easier to create and manage multiple objects with similar properties and behaviors.

How does the speaker differentiate between attributes and methods in OOP?

Attributes represent the information or data associated with an object (e.g., name, address), while methods represent the actions or functions an object can perform (e.g., teaching, preparing a quiz). Attributes are attached to objects, and methods are the actions the object can perform.

Why is everything in Python considered an object?

In Python, everything is considered an object because all data types, such as integers, strings, and even functions, are instances of inbuilt classes (e.g., int, str). This object-oriented structure allows for consistent handling of data and operations.

Why do we need classes if objects are important in Python?

Classes are needed because they provide a structured way to define the properties and behaviors of objects. Without classes, managing multiple objects and their attributes or behaviors would be chaotic and inefficient.

What is the syntax for creating a class in Python?

To create a class in Python, you use the `class` keyword followed by the class name in Pascal case (e.g., `ClassName`) and a colon. Inside the class, you can define attributes and methods.

What is the difference between free-floating variables/functions and attributes/methods?

Free-floating variables and functions are not associated with any object, while attributes and methods are tied to a specific object. In OOP, attributes hold data specific to an object, and methods define the object's behavior.

What assignment is given at the end of the video?

The assignment is to create a class called `CarDesign` and then create two objects of that class. The task is to practice defining and using classes and objects in Python.

Outlines

00:00

💻 Introduction to Object-Oriented Programming in Python

The speaker begins by addressing the audience and checks on their well-being. They then dive into the topic of object-oriented programming (OOP) in Python, emphasizing the shift from procedural programming due to its limitations in handling complex, real-world projects. The previous video introduced the concept of OOP, explaining the need for it over procedural programming. This video focuses on classes and objects, explaining the syntax for creating classes and objects in Python. The speaker uses the analogy of a YouTube channel to illustrate how OOP simplifies relationships and reduces project complexity. They discuss the idea of a class as a blueprint for creating objects, using the example of instructors within a YouTube channel. Attributes and methods are introduced as ways to represent the information and actions of an object, respectively. The video concludes with a reminder that everything in Python is an object, and classes are necessary to define new data types that don't exist by default.

05:02

🏗️ The Importance of Classes as Blueprints

In this paragraph, the speaker uses the analogy of an idli maker to explain the concept of a class as a blueprint for creating objects. They argue that without a design or blueprint, it would be difficult to create objects efficiently. The idli maker simplifies and speeds up the process of making idlis, just as classes simplify the creation of objects in programming. The speaker also compares classes to other blueprints like car models and house sketches, emphasizing their importance in manufacturing and construction. They conclude by reiterating that classes are essential for defining new data types and creating objects, which are instances of those classes.

10:04

📝 Syntax for Creating Classes and Objects in Python

The speaker provides a step-by-step guide on how to create a class in Python. They explain the syntax, which involves using the 'class' keyword followed by the class name in PascalCase and a colon. The class body, where attributes and methods are defined, is indented after the colon. The speaker notes that the class name should follow the PascalCase convention, with the first letter of each word capitalized. They also mention that if a class is empty, the 'pass' statement should be used as a placeholder. The paragraph concludes with a practical example of creating an empty class named 'Instructor' and an object named 'instructor1' from that class. The speaker demonstrates that even though the class is empty, it can still be used to create objects, which can then be identified by their class type.

15:04

🚗 Assignment: Creating a 'CarDesign' Class and Objects

In the final paragraph, the speaker assigns a task to the audience: to create a class named 'CarDesign' and two objects from this class. This exercise is intended to reinforce the concept of defining classes and creating objects in Python. The speaker reassures the audience that understanding these concepts takes time and that further videos will cover additional details, such as adding attributes and methods to classes and introducing the constructor method. The video ends with a farewell, promising more information in the next installment.

Keywords

💡Object-Oriented Programming (OOP)

Object-Oriented Programming (OOP) is a programming paradigm that uses 'objects' to design applications and programs. It is a concept central to the video, as the script discusses the shift from procedure-oriented programming to OOP due to its ability to handle complex problems and large-scale projects more efficiently. OOP models real-world entities as objects, which can contain data in the form of fields (often known as attributes) and code, in the form of procedures (known as methods).

💡Class

A 'class' in OOP is a blueprint for creating objects. It defines the structure of an object, including its properties (attributes) and methods (functions). In the script, the class 'instructor' is used as an example to explain how classes act as templates to create multiple objects, each representing an instructor with their own attributes and behaviors.

💡Object

An 'object' is an instance of a class. It is a concrete entity that is created from a class blueprint and has its own state and behavior. The script uses the example of 'instructor' objects like Jenny and GR, which are instances of the 'instructor' class, to illustrate how objects are created and used in OOP.

💡Attribute

An 'attribute' in OOP refers to the properties of an object. It represents the state of an object and can include data like name, address, or any other relevant information. In the script, it's mentioned that each object, like an instructor, has attributes such as name and address, which are specific to that object.

💡Method

A 'method' in OOP is a function or a procedure associated with an object that defines the actions an object can perform. In the script, methods are illustrated by the actions that an instructor object can do, such as 'teach' or 'prepare quiz', emphasizing that methods are tied to the object's behavior.

💡Procedure-Oriented Programming (POP)

Procedure-Oriented Programming (POP) is a programming paradigm where the program is thought of as a collection of procedures or functions. The script contrasts POP with OOP, highlighting that POP is not as effective in handling complex, large-scale projects as OOP is, due to its inability to model real-world problems effectively.

💡Blueprint

A 'blueprint' in the context of the script refers to the design or plan from which objects are created in OOP. Classes act as blueprints, defining the structure and behavior of the objects that are instantiated from them. The analogy of an idli maker being a blueprint for making idlis is used to explain the concept of classes in OOP.

💡Instance

An 'instance' is another term for an object in OOP, indicating that it is a specific occurrence or copy of a class. The script uses the term interchangeably with 'object', emphasizing that each object is an instance of its class.

💡Constructor

A 'constructor' in OOP is a special method used to initialize new objects. The script hints at the concept of a constructor by mentioning the syntax for creating an object, which includes parentheses that might contain constructor parameters. The constructor is crucial for setting up an object's initial state.

💡User-Defined Data Type

A 'user-defined data type' is a type that is created by the programmer using a class in OOP. The script explains that classes allow programmers to define their own data types, which can then be used to create objects. This is in contrast to built-in data types like 'int' or 'string', which are predefined by the programming language.

Highlights

Introduction to object-oriented programming (OOP) in Python, discussing its advantages over procedure-oriented programming (POP).

Explanation of why object-oriented programming (OOP) is used in industry for handling large, real-world projects.

Review of the previous video covering the basics of OOP, classes, and objects.

Example of a YouTube channel simulation, where instructors, editors, and social media marketers are modeled as objects in OOP.

Discussion of attributes and methods: attributes define the data (e.g., name, address) of an object, and methods define the actions (e.g., teach, prepare quiz).

Explanation that in Python, everything is an object, even variables like integers and strings.

Introduction to built-in Python classes like `int` and `str`, which are used to create objects.

Explanation of the importance of classes as blueprints for creating objects, using examples such as an idli maker, cars, and house blueprints.

Analogy of a class being like a design or blueprint, while objects are the real-world instances created from that design.

Clarification that a class in Python is a user-defined data type, allowing the creation of custom types.

Introduction to the syntax for creating a class and its objects using the `class` keyword.

Explanation of the Pascal case convention for naming classes in Python (e.g., first letter of each word capitalized).

Introduction to the concept of constructors and the importance of the `__init__` method in Python classes.

Explanation of the `pass` statement to temporarily define an empty class or function.

Assignment for viewers to create a class called `CarDesign` and instantiate two objects from it.

Transcripts

hey everyone I hope you all are safe and

doing good so in the series of learning

Python programming language we are

discussing object oriented programming

in Python

previous video was about like that was

introduction to oop what is an op and

why we need oop that we have discussed

in previous video because there are some

drawbacks in the procedure oriented

programming approach pop approach that

is why we we are using oop right and to

sum what we have discussed like what is

a class and what is an object in the

previous video so please watch out that

video first and then come to this video

then you will get in better right now

more about classes and objects we will

be discussing in this video and how to

create your own class the syntax of

creative class and object why basically

we need a class

that thing we'll discuss in this video

right so if you remember the previous

video then we have come to this thing

like we have taken an example of a

YouTube channel

right

so how you can simplify the relationship

and how you can you can you know reduce

the complexity of a larger project with

the help of this Paradigm with help of

this approach and that is object

oriented programming

in the previous video we have concluded

that like the pop approach is not able

to handle real world project we cannot

model real world project or real world

problems using pop approach pop approach

cannot handle large project very large

project

you know that is why at Industries in

companies The Coop approach is being

used while implementing the projects

right so now we are creating like a

virtual YouTube channel right so like I

was the manager and I have

instructor I have had instructor then I

have editor and social media marketer to

handle their respective job right now I

have hired like two instructor Jenny and

gr to teach different different subjects

right so these were objects and the

instructor was class so it was just a

blueprint to create objects

right

right so we know like object oriented

programming is used to model real world

problems Real World objects right so

every object is having some information

and will do something like I am an

object

so I'll have some information like name

phone number address and I'll do

something maybe I'm teaching

right so what an object have that we can

model with the help of attributes and or

you can say variables and what I do or

what an object do that we can model with

help of functions or methods in

programming using oop approach right

here like

and stuff that is having this thing this

information name address and has book

has camera has laptop and all and what

the instruction instructor will do teach

and prepare quiz so these are methods or

functions see we do we don't call these

simple variables and functions we call

these attributes and methods why so

because these are associated these are

attached

with the instructor

like name is equal to Jenny address I

have some address so these name and

address are attached to me these are not

free floating variables so these are

attributes that is why we call these

attributes and the functions like I

teach I prepare quiz these are also

attached to me if I am an object right

so that is why they are known as methods

not just simple functions that are free

floating in your program no right that

is why these are known as attributes and

methods

right now see everything in Python is an

object

in the previous video I have you know

given you one example also simply if I

write X is equal to 1 and if I print

type of this x then what you will get

class ends so this x is an object of

Class end the class is inbuilt class if

I want to find out like x in x I am

having hello

so this is the string so in this at this

time it will give class as Str so this

is string this hello or this x is an

object of class Str same with function

in the previous video I have shown you

this thing practically right so we have

inbuilt classes in Python and we use the

object so

objects are more important everything we

do with the help of objects right

because this x is an option X1 this is

an object if you create a function that

is also an object right so objects are

very important we do everything with the

help of objects in our python Python

Programming right then if objects are

important then why we need classes

right let's take let's understand this

thing with the help of this example see

suppose like you have an idli maker

right so this is an idli maker and you

put that better or that stuff here in

this early maker and your idli will be

ready in next maybe I don't know the

recipe proper maybe 10 to 15 minutes

within 10 to 15 minutes right

so the idli you are having

these are actual objects and the idli

maker what you have that is just a

design

to make to prepare idlis

right

and if you don't have this design then I

think it would not be easy for you to

prepare idli maybe you can prepare with

the help of some other method I don't

know but

if you have the steadily maker then it

is very easy for you guys to prepare

many idlis

just in just you know few maybe hours or

few minutes

right

so this idli maker is going to make your

thing to make your you know process of

making idli is very smooth and simple

and quick right so it is a design same

if you relate this thing with like of

example so class is just a design or

blueprint so obviously to create object

to create idli

we need idli maker so we need a class to

create object we need a class that is

why classes are important

same like if you have any car

it may be greater

so there are like suppose one million

krata in India right I don't know the

number but this I'm just supposing this

thing so there is a model there there is

a prototype there is a design of that

car crater and using that design they

are creating multiple craters

in less amount of time so that design is

important that blueprint is important

same like

third example we can take like a map of

a house or a sketch of a house

right using that sketch we can create

house houses many houses so that house

you create a object the real thing that

is an object and that map is just a

class or a blueprint but using that

blueprint you can create multiple house

multiple houses

many houses

right and if you don't have that map

then definitely you can

build or you can construct a house

but if you have map then it would be

easy and you know simple to build a

house to construct a house because there

are many people

working there and one who know like what

is the map exact planning like what to

do next then he or she can easily guide

the contractor or anyone he can he or

she can easily Guide to the members what

to do next if you don't have map then it

would be not that much easy

to communicate so relationship would be

tough

right so now I hope you got the idea of

class and object and why we need class

class is also important right so we can

say this class is just a blueprint or a

design to create object an object or you

can say instance we can also say object

is an instance of

that class or instance of a class

right

or we can say class is a user defined

data type user defined type

why I'm saying so because see when you

take X is equal to 1 the type of X is

end

when I say x is equal to hello

then the type of this is

it is of class Str it is of Class end so

these classes are inbuilt classes

right like in test year or many classes

we have Boolean also we have float

double

right

so if you want a variable something like

this so the type of this is already

defined like int but if I want like uh

if like Jenny an instructor

so this would be of

I like this is not any type like I'm not

providing it as a string but Jenny is

like an object it is having some

information like me as an actual person

real person some information I'm having

some task I do right

so for this we have to Define our own

type

right so that we can Define with the

help of like class keyword and whatever

class name you give right so class

simply we can say it is a user defined

data type also okay this thing class is

a user user defined a type that you will

get it at the end of this video don't

worry if you are not getting this right

so syntax of creating a class how to

create your own class just class keyword

and

class

name

and column

and here obviously the data what you

want to right here that reviewed and the

methods and that also we'll see

right the class name is in Pascal case

it means the first letter of each word

is capital letter like class the name n

like our name so J is capital K is

capital like this

so we use this

uh like no you can say the what I should

say this I'm not

I'm not getting the exact word it's okay

so this is you can say some kind of rule

you have to use a pascal case to write

down a class name

like for for creating variable name we

simply use like underscore

like maybe I don't know like user

underscore name if a variable then we

use underscore this is a

first

is what

first is letter is small and for each

other words

the first letter is capital this is the

only difference between Pascal and camel

keys right

so

this is how you write class class or if

you write like something like this first

is small there is also small that also

will be fine it will not give you any

error but that is some kind of

you know rule or you can say this kind

of thing right just to differentiate

between a class name a function name or

a variable name something like this

right

so

like this we write class name fine this

is the syntax simple

and here you will write whatever you

want to like attribute methods and all

that also we'll see now how to create

object if from this if suppose class

name is instructor

if I want to create object of this class

then

maybe I am like

writing instructor underscore 1 is equal

to just the object name then class name

last name is

instructor but this is not it

this you need to pass

the these brackets down brackets

so this is somewhat like Constructor now

what is Constructor that also we'll see

but this is simple syntax of creating an

object let's see this practically okay

so let's create a new file

op Concepts classes dot p y

so how to create your own class just

class keyword

and class name so I am

creating a class instructor

so chemical sorry Pascal Pascal cases

first is

capital and if the next if you want to

write them like information i n f o info

then I would be again Capital so this is

Pascal case every letter of the word

would be Capital so just instructor and

then column right now

okay I'm not passing anything in class

no attribute no method so maybe you

think this is an empty class right and

I want to create object of this class so

instructor 1 the name of the object is

instructor one and then equal to the

name of the class instructor and just

these brackets but see now can you see

this red line here so this is an error

like this indent expected

so same with function I think you have

seen if you create function then you

cannot you know leave that function

empty you have to write down something

but I'm not I don't want like I I don't

know how what to write in this class

right now I don't know the syntax how to

write attribute and methods so I have

told you one

statement we have passed

so that you can select just write down

here pass so maybe further I'll do

something here but right now I don't

know what to do here so just write down

their path so now see there is no error

right so this is how you can create your

class and this is how you can create an

object

so if you run this then there would be

no errand but no output you will yet

obviously

now if you want to find out the type of

this object

type of the object

instructor one because name of the

object is instructor one right this is

the name of the object we have created

so what would be the type of this object

let's run this

see the type is class is just focus on

the class instructor

right although we have underscore

underscore main underscore underscore so

that this thing I'll be talking in later

videos right but now you have to focus

only on this name instructor right so

now we have created our own type our own

data type that is why I have told you

that line like class is a user defined

data type as

now as many object as we want we can

create from this class from this time

instructor One Two Three or many objects

many instructors

right but all would be of this type

class instructor so this is a user

defined data type that actually acts as

a blueprint to create objects right and

object is just an instance of a class

right now one assignment for you is you

have to create a class and the class

name would be car design

car design this will be the name of the

class

right and you have to create two object

of that class

right so this is your assignment you can

write them that thing in comment section

so now I hope you got what is a class

what is an object what is objective

programming how to create your class how

to create an object right if you are not

getting this if you are still getting

like 50 then it's fine

not slowly you will get everything in

later videos right now in the next video

we will see like how to add attribute to

your class and there is a method like

init

that also we will see

in next video like underscore underscore

unit underscore underscore then in

bracket self so what is this method that

we will see in next video what is

Constructor and this kind of concept

right

so I'll see you now in the next video

till never bye take