Python OOP Tutorial 2: Class Variables 

Your videos are more informative than my university lectures

Summary: In this video, Corey taught as how to differentiate between a Class variable and instance variable, how they are related to each, other, and when each of them is more useful over the other. Class variables are variables that we set inside a class, and are shared among all instances. Corey gave a good example where the number of total employs should be the same to every employ, no matter which employee we are referring to. Therefore, emp_1.num_of_employ = emp_2.num_of_employ = Employee.num_of_employ Instance variables are variables that are different from each instance. For example, the names and the pay for each employee. They have to be different. Corey also shows that class variables and instance variables are closely related, and that class variables are kind of 'inherited' to the 'self' variables. To illustrate this, Corey shows an example of 'annual raise of pay'. He initially creates the class variable to show a case where annual raise is equal among all the employees. This variable of 1.04 was accessible through each instance, and also through the class itself(obiviously). That is, print(Employee.annual_raise) print(emp_1.annual_raise) print(emp_2.anual_rais) all printed out 1.04. However, using the .__dict___ thing, Corey shows that the intances, emp_1 and emp_2 does not contain the annual_raise value. Corey explains that if a variable is not found within an instance and programmers try to access the variable, python automatically looks in in the variable of the instance's class, and then the more classes that the instance's class inherits from. Furthermore, if we access the class variable through an instance and then change it, python creates the variable within the instance. We can check it by using the .__dict__ thing. Corey shows that annual_raise key was created when he manually changed the annual_raise value as 1.05 in the following way. emp_1.annual_raise = 1.05 however, we know that the class variable remained the same at 1.04, when printing the class variable. print(Employee.annual_raise) ==> 1.04

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This is so good that I'm starting to doubt whether all his 'mistakes' are secretly ways to make us learn faster :P

it really makes a difference who teaches you.....it was wtf wtf wtf....then watch these videos...oh ya that's logical. you are an awesome teacher....please keep the videos coming.

The sleepless hours that I spent trying understand the nomenclature and the functions that he just made clear in 11 minutes... if you had an advanced professional class that cost money, I would pay for it.

Who needs a Udemy course when you have Corey on RU-vid. Thanks buddy for making internet useful for us.

I finally understand the difference between teaching and throwing information. Love your explanation Corey!

This series is the best Python series I've ever watched. Your explanation is so clear and you just teach the right amount of useful knowledge we need.

you helped me get an internship. :*

6 years later, and your videos are still helping us students. I'm in highschool and I'm literally studying for my exam through these. When I pass it'll all be because of you. THANK YOU COREY!

You have the best python OOP tutorials. Thank you, you are helping alot of people especially aspiring developers from Africa. Cheers

I know there loads of comments appreciating your work already, but man.. . I started learning python about 1,5 months ago and I have never learnt about OOP, not even its concept and the difference related to other types (still dunno them properly), yet I fully understood everything you said in both of your videos so far... Hats off dude.

So, 5 years ago, this amazing video was made and I'm just seeing it in 2022! What a classic teaching it is! Thank you for the supremely brilliant delivery 👍

You are an outstanding teacher, showing the reasoning behind things is MASSIVELY impactful. Feels like my brain is expanding watching your videos lol

Best Python OOP lessons for beginners!

These videos are insanely good... Definitely not for a 100% noob but absolutely amazing for somebody who's hacked around and now needs a technical understanding to get to the next level. Thanks, Corey!

I'm so so so glad that I found Corey on RU-vid. His teachings are state of the art! Whenever there's something I'm confused about python, he is the first person that comes in mind. I'm so very grateful to have you as a teacher, you rock at it! Keep it up! Can't wait for more!

This guy is insane at teaching, thank you so much!

I don't know why you don't have more subscribers by now, or maybe there aren't many coders out there. But I was afraid of starting learning Python until I stumbled onto this Chanel. Now I can code as a charm.

Wow! Learned more about classes and class variables, in the last 10 minutes, than on a full day going through online python CBT. Can't wait to watch the rest of this series.

I read a ton of explanation for class attributes and instance attributes, but you explain it so clearly. Great job!

It's great that there are people with pedagogical grace, but it's really wonderful when they share their knowledge with beginners. Please don't stop what you're doing ❤

Hi, I need to say your videos are really clear, comprehensive, enough detailed but not boring and too long on the other hand. I just sent you some small donate right now as appreciation. I wish I discovered your channel sooner. Thank you for all your effort!

Showing the namespace was so clever to help us thoroughly understand it. Thank you so very much!

hands down the best OOP tutorial series... I've been using python for 2 years, but have been intimidated by Classes.... this has helped a ton!!!!!

OOPs tutorial couldn't have been more better than this.Respect from india, Mr.schafer.

What I love about these lecture, that Errors are explained, which is more intuitive. Thanks Corey :)

Quality tutorial! You got my patreon backing.

Your pretty much the only thing and/or person who explains any of this clearly

Corey, your videos are EXEMPLARY :) Your approach to teaching, and examples you use (e.g. Employees), have finally unlocked the hard-to-understand concepts into easier-to-understand analogies. Thank you for posting these videos!

Going through your videos we feel like we have covered the most. What we can gain by going through multiple books you walk us through it in one video. Thank you Corey from the bottom of my heart.

On the 2nd of Feb 2020 ,this video had a 99.64% like - dislike ratio. That's insane. It stands as a testimony to the insanely great work Corey's been doing. Thank you!

As a beginner, I was stuck with learning Python Class and so lucky to find these videos via Google search! Very informative and easy to understand. BTW, the teacher in these videos also has a nice voice ☺

The best python OOP tutorial on RU-vid. Thank you sir

You start with messing up the things, then collaborate them and make a great sense. Awesome.

I've seen several sites, books, and videos that all used the Employee class as an example for OOP, however this is the only one that actually made sense and helped me understand the concepts. Thanks!

Hello Corey, I'd like to thank you for all the courses on Python you've made. They're way better than udemy courses and any others. You're doing a great job, captain!

As a CS person myself, I’ve seen numerous tutorial videos. Yours is the most logical, right to the point, and easy to understand. 👍 Hope you’ll create more contents.

Senior here and taking a different online course just to keep the synapses working. Well, you have it way over them in teaching quality. Wish I had seen you first. Thank you.

After working in the industry for 5 years, learned this concept today, just because of the way you made it. I am moving towards into a more coding technology and your videos are gold! Amazing!

Corey your explanation of "Class" is just that...... CLASS. Perfect explanation!!! Total Respect.

Mind blown..!!! 20+ years ago I was working with Macromedia (Macromind) Director and as a visual designer without coding knowledge or experience I struggled to master Lingo. Over time I ended up at the level of an OOP Lingo coder, albeit one relying heavily on copied code segments and fiercely treasure code examples that I'd gotten to work. FF 20 years and I've returned to coding in the form of Python. SUDDENLY with your videos a window has opened on the murky interior I previously inhabited. I now understand the concepts that you are talking about rather than piecing together code samples. ALL of your videos that I have worked through have been enlightening, fun and edifying. Thank you so much for giving all of this.

This is just pure gold. That's how any teacher should be , who makes their student eager to learn more in most simplistic way. Great work Corey.

I was thinking i am very good in OOP since got i A+(4.0) in the course both in Theory & Lab, somehow i came to the playlist & saw pretty amazing comments, so i got interest to see what's inside. i was thinking myself a pro in OOP. But the way you teach things here are amazing.

This is the type of youtuber whom I would gladly watch 10 straight ads on their video

As somebody who used C# for years, and is now picking up some python. Thank you for clearing up some of what I saw as weirdness with the way python does things. Its all clear now and simple.

COREY is just the best teacher ever!!!! Thank you COREY!!!!

I have NOTHING BUT PRAISES for your style, clarity, and to the point explanation of VERY IMPORTANT concepts .... I cannot thank you enough Corey .. I will gladly contribute to your classes and start filling all the "gaps" of knowledge I need to .. You have a devoted student now :)

Absolutely freaking awesome. Hands down, you're providing me an A+ headstart for my bachelor course in economy informatics. Huge thumbs up for spreading absolutely logic and understandable explanations. You're amazing. Thanks.

You are so thorough! I agree with others that you are a natural teacher. The pace, tone, comprehensiveness, and genuine enthusiasm are all spot-on. You are an asset! Thank you!

Posted 4 years back but still, I did not find any other tutorial as clear as these classes one. I have just started learning python and I really appreciate you making these videos. You are an awesome teacher.

This is the best Video ever to explain classes, i have been very lost for a month trying to get this concept and you explained it in less than an hour thank you soo much. I am going to nail my computer science paper tomorrow

I've been watching several python training videos. Corey explains things more simply and more completely than anything I have watched so far. Good work.

I first started watching these videos to help my son, who is currently taking coding courses. I found your videos very very helpful. Thanks a lot, Corey..

Dude I miss your videos. Best python videos on youtube. I hope you come back and start uploading more valuable videos.

I get more explanations from your videos than what I have got from all of my courses, great work!!!!!!

Oh My God. I was struggling with OOP concepts. Corey made it so simple. Corey keep on doing what you doing my good friend. Thank you.

Just want to say thank you for these videos. I took the wrong path in my education before realising that programming was my true passion. Unfortunately its really difficult to self-teach something like this because of the sheer wealth of information avaliable online. Your videos cover almost everything I've wanted to learn so far, and not only that you don't just 'show' you actually teach. Every time i find myself asking a question about something you've just said, you immediately address why it and explain why it may be confusing. Thank you so much for putting in the time to do this and make it free, you are really making a difference to peoples lives.

These are the best videos ever . I struggled to make sense of these concepts before . Now its all so damn logical and intresrting. A Million tonnes of gratitude to u !

Tank you for covering all of this. I'm truly becoming better in Python because of this

Thanks for making a concise and understandable lesson on 'self'. I had one semester on python and my professor could never really make it make sense and you managed to explain it is like 20 minutes. Heck yeah!

What I loved about these tutorials is that he tried to cover those tricky questions such as instance namespace and class namespace ever for people that are already familiar with these concepts. Keep making videos. Your content is great!

Being from a non-technical background, I was struggling to understand the OOP. But now the concept is clear to me. Thank You..

Thank you so much for this series, these videos are fantastic, I feel like every possible pitfall or misunderstanding one could have you articulately and expertly explain.

This is the most logical approach to class and objects, i am really glad i found you Sir! Thankyou for such a beautiful explanation. You solved every doubt!

Your videos are more much effective for me to learn computer programming for my personal gain.

i am a beginner to python, on searching many videos in youtube i found your bunch of videos. so nice and so easy to learn, very interactive and you have pointed out every small and basic things. thank you so much.

Lol your explanations are better than all my professors. How did I not find this channel years ago smh

You, sentdex, Traversy Media are the teachers we all need in Uni but don't have. The day I get a job, I'll definitely support you. Thank you for sharing your knowledge.

I know most of the other comments have expressed the same feelings a year or two before me, but these are the best tutorials for object oriented programming in python that I've found. It 100% cleared things up for me. I feel like I can finally move on!

Don't know how to express how grateful I am to have all these materials. Thank you a lot Corey.

your videos are much better compared to many online courses and free too

This is so much better than my lectures and book, thank you so much!

Everything you explained is clear and logical. Thank you

Probably the best videos Ive been able to find for beginner Python. So articulate and logical in the way you teach, it's awesome. Thanks.

can't express how nice and easy to understand these videos are

BEST PYTHON OOP EXPLANATIONS I HAVE SEEN. I HAVE BOUGHT MANY ONLINE COURSES BY THEY ARE SUCKS COMPARING TO YOU.

Absolutely masterful. I rarely even need to rewind, that's how well you explain it. It's like magic.

I tried watching these videos several months ago... all went over my head. Now the lightbulbs just keep popping!!

You are literally giving me hope, appreciate it

Everything is so well placed and informative, thank you!

Your videos should be at top in the youtube search for "python". I'm recommending your channel to all my friends interested in Python. Thanks Corey. You are a great teacher.

You helped me finally understand object oriented programming in just one video after hours of surfing the web without any result.

1 hour of my Grad class summed up in 11 minutes. Thank you!

Dude, these tutorials are mindblowing.. I've gone through a few OOP classes and never really understood the concept so i can write my own things with it, after watching tutorial 1 and 2 i now have a very good understanding how to rewrite a whole script i got. Thanks, i never sub but this deserves a sub.

Bow down to the maestro...the way you teach is still the best after 5 years of this video...I have been to lots of tutorials for python but always missing the concept...you made it like a butter in the frying pan...it just slips through your mind and I feel satisfied after learning from your videos.... please don't stop your videos...the world needs teacher like you ... #respect

You are amazing man!!! so simple, so clean and straight forward. Every minute brings a new information

Corey, to repeat the sentiment here, you really helped drive home what Object Oriented Programming almost instantly. You should have your own Coursera courses.

Best RU-vid channel there is! Bravo!

The best Python tutorials I have come across. Your explanation is just awesome. Keep up the good work.

The best explanation on Python Classes on YT. Congrats, man

After purchasing a few tutorial classes going through the online material this is where i got the bestsellers explanation. #Thanks Corey Schafer #Respect

You are next level, man. Respect!

Dude, you're amainzg! You're tutorials are one of the best tutorials i've ever watched! Good work!

I could cry. I wrote a program that needed to automaticly create Buttons and I sat down there for like 5 hours to do this but now I can easily make the same program in 5 minutes and a third of the code. Thank you so much!!

Finding your channel is like finding a Gold mine Corey , keep up the Gold work ; - )

You might have no idea how helpful this was to us.

Thanks Corey, your videos are just fantastic. You put things across in a way that can be easily understood and I'm just hooked onto these videos

Thanks Corey, I am Chartered Accountant in Ghana learning to code with python, your videos are so helpful. Thanks once again.