Everything you need to know about Classes in Python! (Object Oriented Programming Tutorial)

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In this video we overview the main things I think are pointing when you are starting to learn about classes & integrate them in your everyday code. In this video we cover:
- why should we use object oriented programming (oop) ?
- the basics of defining a class in python (__init__)
- class methods
- what the heck is "self"?
- Inheritance & Subclassing
- Operator overriding
A timeline is in the comments.
If there are topics you felt like I left out, let me know in the comments! I'll potentially make a follow up video to this one.
For an example of me structuring my code with classes, check out this machine learning video: • Real-World Python Mach...
If you want to practice using classes, try rewriting the game we build in this video to use them: • How to Program a Game!...
^(I'll update the github repo for that video with my solution to this soon)
Resources:
Github code: github.com/KeithGalli/python-...
Operator overloading: www.geeksforgeeks.org/operato...
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Video timeline!
0:00 - Introduction
1:34 - Why use classes?
2:27 - Defining our first class in Python
6:05 - Class methods
13:53 - Passing in default keyword arguments (size of our polygons)
20:18 - Inheritance & subclassing (using the super() method)
24:43 - Class method overriding
26:06 - Plotting points with classes
28:09 - Operator overloading
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If you are curious to learn how I make my tutorials, check out this video: • How to Make a High Qua...

[@KeithGalli]

Video timeline! 1:34 - Why use classes? 2:27 - Defining our first class in Python 6:05 - Class methods 13:53 - Passing in default keyword arguments (size of our polygons) 20:18 - Inheritance & subclassing (using the super() method) 24:43 - Class method overriding 26:06 - Plotting points with classes 28:09 - Operator overloading Thanks for watching! Please consider liking & subscribing if you enjoyed this video :).

[@theultimatereductionist7592]

My experience with all computer programming, 40 years of experience, starting with Fortran, then C++, Java, LaTeX & TeX typesetting, and now Python, is that it is such a colossal waste of effort. To spend 40 years trying to figure out the meaning of one piece of syntax, and then succeeding, only to have never made any money during those 40 years because all one did was try to figure out what that one piece of syntax does or means, is the understatement of understatements of Pyrrhic Victory. I honestly now hate it more and learn and understand less of it now than at any earlier point in my life. At least taking formal community college courses got me to understand and do something with programming. But literally there exists absolutely nothing PRACTICAL that one can do with computer programming in ANY language outside doing formal college course work for a teacher. I mean, sure, just to make the codehead morons & idiots happy whose entire life is wrapped up in fetishizing and worshipping and oohing and aahing at one language using a period and another language using a ? mark to delimit a command or whatever, believe it's the greatest thing since farming & anesthesia when I figure out how to get one line to work, before getting stopped for the next 10 years by the next 200 lines of code. To teach me programming, you would have to personally live with me and work with me every day for 10 years, and pay me $30,000 a year to do this thing I hate. Best to stick to proving mathematical theorems. At least, when one finally triumphs after 30 years trying to solve that, one has added new deep original knowledge to the collective knowledge of humans.

[@JK-jt3lr]

If you want to add more points at once, use the __radd__ function.

[@kevy1967]

I’ve just returned to programming. I grew up in the 1970s/80s programming an old TRS-80 in basic. I’ve just started learning Python and have been struggling with classes, so, thank you. Your video and style of teaching was excellent and I finally think I can understand now.

[@moniquemarshall2161]

I've always struggled to understand the usefulness of classes, and this video communicated it really well with great examples. Thanks for always producing quality content!

[@johnwu7509]

I had lots of trouble understanding classes. I watched no less than 5 videos and went through many sites and this video really helped me to understand. Great job!

[@samkons280]

These days when I am looking for a lesson, I always have to include in the search '...by keith' and even if don't KZbin brings your videos first because they know my preference!. Such a great teacher, I have followed through many of your lessons decided to shout out on this one. Keep being on fire.

[@ikki411]

I already knew most of this stuff, but you teach so well that it was really nice watching this video!

[@jeremycollier4377]

Hey Keith! Amazing video. I found this video because I wanted to truly understand the basics of classes and you did such a great job of explaining it in a simplistic way. Not to mention showing off some cool visual libraries! Looking forward to see what other videos you have.

[@FreihEitner]

This was really handy! Between a 5 hour "Nana" Python tutorial I watched earlier and this, I have a greater understanding of OOP than I have had for the past 15 years of off-and-on reading of programming books trying to grasp it.

[@nicholas-ewing]

After learning Python via SoloLearn and having to struggle through their horribly designed lesson on OOP for Python, this tutorial was an amazing help at actually understanding OOP.

[@nikhilprem7998]

Sololearn is a really good free app to learn coding imo also the community is great

[@jessegreer9]

I have built a couple of basic classes but I’m writing one to auto do a bunch of freq calcs that is a lot more complicated. 10min into your vid and I finally got a work in progress. Thank you!

[@osezeestheriyore8612]

Great video! Can you do a 'solving real world data science problem'-video using classes?

[@ktejakrishna9620]

For angles, we can use simple formula, exterior angle for n sided polygon = 360/n, and in draw method, we can use left instead of right as below. turtle.forward(self.size) turtle. left(360/self.sides) We can get the polygon drawn

[@n8trh]

Yes, this! When I took a Python class my first year at my university, they used this method to draw pentagons with the turtle package. I realized in class that this method was not only very intuitive, but also could be used for what became my favorite derivation for the interior angle formula of a regular n-gon (or by extension, their sum formula).

[@ferdinandolongoni9246]

Man, you're saving my days! I want to make a snake game in python and saw some tutorials on the ytb and found nothing that i could totally understand. Then I saw you Python Game Tutorial and learned so much! Besides that, I saw you GUI tutorial and learned so uch about Tkinter too. So, thank you so much and continue doing this awesome job! Regards from Brazil

[@VinodKRamachandra]

This was one of the best videos i have seen on python classes. Thanks a lot for sharing

[@MrRadzor]

This channel is underated af . Great work my guy !

[@brijpathak3873]

You're a great teacher. Thank you so much :) You'll def. know how classes work in Python after watching this!

[@frankcasanova2132]

i´ve see a lot of videos about this issue in youtube, and your video it´s the best. greetings from spain!! keep going!

[@greg_715]

I did not understand classes at all until watching this. You did what my university lecturer couldn't. Thanks a bunch!

[@camerongoodhue9552]

Cheers Keith, so good. The polygon example is the best one i've seen as a beginner.

[@_sofigeek_9452]

Very well done! Now it is so beautiful, to see and understand the concept of object programing language. Thank you, Brother.

[@AngeloSomers]

More helpful than any other tutorial I’ve seen, Thankyou!

[@hanqie11]

One of the best explanations of oop. Thank you! Love the way you get enthusiastic when talking about sub classing around 24' :D So nerdy

[@KeithGalli]

Glad you enjoyed! And lol yeah gotta love subclassing 😁

[@JoePescisAngryCousin]

Dude, this video is great. I learned so much. You're an excellent teacher.

[@LookNumber9]

Super useful! Very clear and concise explanations throughout. Thanks.

[@symnshah]

This is the best explanation of Python Classes, much much appreciate it.

[@jessethomas7009]

choosing to do shapes for visual aid was a great idea this was really helpful !

[@larslover6559]

You are "my kind" of teacher. Going forward in a relaxed nice progressive way. You being a graduate from the best university in the world certainly gives you credibility too, haha. Keep up the good work!

[@jamesferguson5233]

Straightforward and clear...great technique you use to demo these concepts...thanks so much from a budding old geezer hobbyist!

[@wilmermorales]

oh man, your tutorials are the best I have found!

[@tuckerboan2363]

I usually see examples of people who use the Name, age class. This one is much better because you actually do one that's much harder but you explain it so well. Thank you so much for this video.

[@adityawadikar9326]

This is by far the best video I've seen on KZbin for this topic .Thanks a lot Keith

[@KeithGalli]

Glad you enjoyed! :)

[@mikuculus3720]

My book taught me basically everything but I didn’t know what any of it meant this video is great for understanding what you’re doing!

[@kpaxo123]

Great video and that lo fi jumper is 🔥

[@drpwnage23]

Thank you Keith, I learned so much in this video. Subscribed

[@monagulapa3022]

You are a very talented person. Because you can explain complex ideas in a simple way new learners can understand. And as always, Thank you for your amazing tutorials! :)

[@kkopchynski1]

Great video! To elaborate on some previous comments that suggested 360/n: The reason this works is that you are using the EXTERIOR angles in turtle geometry, and the exterior angles of any regular polygon always add to 360. This is the classic "Turtle Trip Theorem"

[@BrianFischer]

Fantastic video, thank you for putting this up. Looking forward to watching more.

[@JUDOGAR]

Amazing video! Thanks Keith! We wait for more of them!

[@ClockDesignCo]

probably the only vid on classes that have made sense of it to me

[@tensianne]

Thank you for this video! I really like the way you explain things.

[@muftizyo8939]

My unviersity/college teachers just gave us a debugging assignment with all __init__, subclassing too and I was so confused, this was very helpful

[@danielholley2495]

This is an outstanding video. Thanks for taking the time!

[@josephhauser9231]

Most helpful video I've seen yet!

[@wehibebelachew3527]

Very helpful tutorial and thank you for your time

[@rantan1618]

This was a great video, i finally am starting to understand classes in python because of this video, thank you.

[@portfedh]

Same here. Thanks!

[@lastpercent9767]

i dont have words u just saved me big time bro thank you so much for making this video print("thank bro")

[@ashleysullivan7965]

Great intro to class; thanks!

[@trevorribbans2256]

First thing I have had difficulty with in Python. Was pumped to find out I can have my buddy from high school teaching it to me haha really helpful video man!

[@KeithGalli]

Hahaha what's good Trevor! I definitely found classes confusing at first too. Happy that you stumbled on this video and found it helpful! Hope all is well :).

[@roywilson9580]

Nice video, thanks for the easy to follow explanations.

[@pythonenthusiast9292]

thankyou for your videos.. I have two video series requests for you : 1) DSA in python 2) Competitive coding with python (if possible)

[@micharudzki9319]

Wow!! I am appreciated for that explanation of Classes in Python. Very detailed information :)

[@sachin2021]

Hi Keith Galli, Your tutorials are simply awesome. I have enjoyed every bit of it. Will it be possible for you to make a small video on polymorphism, encapsulation, multiple inheritance and context manager. PS: the introduction of Glasses..oops..classes...classes in Python was the cherry on the cake.

[@wesleyvanwestenbrugge8369]

Excellent video Keith!

[@jameSM__]

This is the best tutorial for classes

[@CSCrew]

Thanks buddy, it was a great video!

[@darwinpark8228]

thank you from Korea! your videos helped me so much

[@solarenergynow08]

Great and clear video. Thanks!

[@curdrice70]

Superb video on classes.

[@kychemclass5850]

A great tutorial. Thank you so much!

[@fredrickkenamoah9757]

Great tutorials Keith!! Very clear and concise stuff. Grateful if you would do something on Python from A to Z. Regards

[@russellstockley117]

Really enjoying your tutorials,

[@leo_kim]

Thanks for the tutorials! Will you do any content on using Python with Google Docs/Sheets?

[@DrWho2008t101]

Thank you for the video, great work. Appreciate your work.

[@savemyneighborhood]

This analogy is so much easy to understand what class is.

[@jmstockholm]

Well chosen example and leaving some things for later and picking them up at an appropriate point in time like "self". Going into enough details but not to much, i.e. simplified enough (substituting "+") to get the idea, but not to a point where the statement actually isn't correct (e.g. common with metaphors), thus only confusing (smarter) people. Thanks for the effort!

[@KeithGalli]

Thank you! Your feedback means a lot :)

[@gabrielstewart9022]

Best Class Tut Ive found yet! Youre a genius. Subscribeb hahaha

[@briankumanchik2474]

Awesome explanation!

[@christophrathgeber7567]

Such great tutorials! Really great teaching style and great examples! It is really fun watching and learning. Felt so proud when i noticed the missing "self" before you did :D Great accidental attention check :-)

[@KeithGalli]

Glad you enjoy the tutorials! And nice job catching my mistake before I did xD

[@bastianian2939]

Amazing video. Helpes a lot

[@nicholastanzillo4229]

I loved this video, thank you!

[@valenciawalker6498]

Thank you ! For breaking it down .

[@robertknopf6207]

Keith, love your stuff. Been watching a lot of them. Quick question with classes, how would you do a variable amount of subclasses with variable attributes? So using your shape class, have the python program choose from the different shapes, and then choose different lengths, colors, line thicknesses and then store them so that you can refer back to them later?

[@jannealasaarela233]

Thanks!! Well explained! I had to subscribe and like. :)

[@ceesh5311]

21:15 small moment of clarity

[@wiz8058]

😊😊 you nailed it 💯 and best content ever bro. And the glasses at first you got me I thought you gonna teach about blue ray lenses then you came back on track 😂😂😂, but for the video you did great keep it up

[@Amf313]

Thank You.... I have learned a lot from your videos

[@DaveLotito]

21:15 - when you realize you frigged up LOL. Great vid dude!

[@fentonmsu]

Explained it better than my professor, yes told him that your videos are better, in my country they don't know how to explain.

[@krishnadhakad746]

great help buddy thanks a lot

[@alammaravilla8073]

What a tutorial, really great. THANKS

[@gerardomontanoreyes2704]

Great video! what happened at 21:16. Some debugging there Thank you Keith, so much helpful

[@hobbz4921]

great video keith, can you do a video about dictionarys, can you make a mock program that references a random database of some kind please?

[@MalekBenkouider]

Great video, thank you so much

[@WillCastle]

We are learning classes in my programming 1 class and not even our textbook (by person) goes over how to make our modules useful. Our book has been a nightmare our entire semester. Luckily our professor doesn't teach straight from the textbook and luckily I found your video on youtube.

[@tempura_edward4330]

Thank you for this great video!!

[@ibluewolf7937]

Regarding the polygon example instead of: defining Object properties self.interiorAngles = (self.sides - 2)*180 self.angle = self.interiorAngles/self.sides and then using them with turtle.right(180-self.angle), you could just use: turtle.right(360/self.sides) because every polygon has an angle sum of 360º and you want all of your polygon's angles to be equal in each of your sides.

[@psSubstratum]

i love your reaction at 17:32

[@python360]

Maybe mention "Setter" and "Getter" Methods in a follow up video? This video was excellent.

[@KeithGalli]

Good suggestion! I'll probably include that in the follow up vid

[@iqsa021s]

I watched this episode for the first time, so I can understand the object-oriented approach Really thank you very much The only thing I still don’t know much about the usage of __add__, the others are generally understood Student from Taiwan

[@happyagain855]

I think you forgot to incorporate a triangle. I think I will try to do it. Thank you for the explanation man..Great.

[@FaraazQ]

For the next or some subsequent video maybe you could do productionizing a model, making it so we can save a trained model and use it on new data via a flask app or restful API (I know very little about this so if that didn't make sense, sorry)

[@baciukrystyan6479]

Very well explained! Thank You!

[@KeithGalli]

Glad you enjoyed! You're welcome :)

[@mubashir22ful]

Thank you so much bro!

[@mahmudhasankhan7951]

Thanks Keith.

[@mustafaalkan3378]

thanks for kite it looks very handy

[@psyche2739]

I like your teaching style bro! I hope you will create a tutorial in your next video about socket. I have already subscribed and like your video. I think Shape is better than Polygon as your class name. Thanks!

[@jeancarlobejaran3295]

Great video!

[@moritzstrueve5184]

thumbs up for the beginning :D

[@szymonkrupa]

Would be nice to see some practical use of classes in data science (data visualization). Or maybe you know where can I find examples? Keep up good work!

[@KeithGalli]

I agree! Check out my machine learning tutorial, linked to in the description as one example.

[@KlinikXOfficial]

Real good video. However, everyone makes a class inside the same file, a helpful video is calling a class from another file and from another directory would be awesome. Also, you could of simplified the calculations for the angles by doing turtle.right(360/self.sides) and it would of worked just fine haha