Python Tutorial: if __name__ == '__main__'

[@samiam.402]

Dude, it's incredible how simple this concept is when it's explained well. So many other resources had my head spinning about it, but just one 8 minute KZbin video later, and I'm like "oh yeah well obviously."

[@shaheenelt]

p Ppp

[@michaelhagans965]

shoot yeah Sam I am.

[@tanchwa3740]

same boat here I was like what the hell is a __main__ and why should I even care lol. But this makes so much sense. I especially understand someone else's stack exchange comment now about how this is really important for global variables.

[@buddhahead8734]

I'm glad this is where I looked first. It looked intimidating at first, but he made it make sense. Seems like a really intuitive feature.

[@ronakpatel9023]

You spoke my mind man….

[@blmcmcn]

Short answer: this set up gives you the option to run (or not run) a chunk of code when imported from another python file

[@Dorumin]

I got that from the first 20 seconds, it's quite a simple concept for me and I thought up a lot of usecases. Pretty interesting, I don't think I'll watch the rest of the video

[@pulpil10]

@@Dorumin you are so smart

[@Dorumin]

@@pulpil10 Yeah, looking back on this comment it did seem pretty pompous lol, but it really was pretty familiar enough for me to grok like that An example being a chess program that either runs on the command line if you run it directly or offers an API if imported

[@ChrisT-ib1zh]

@@pulpil10 and you are right

[@isMeStranger]

@@Dorumin he explained nothing in the first 20 secs. Does patting yourself on the back make you feel any better?

[@tyroneslothdrop9155]

Subscribed: That was by far the best explanation I've found on KZbin regarding this topic. I hope you continue to make videos.

[@AhmedBalfaqih]

I agree with you. I subscribed based on this video only.

[@Kevin-iu4kj]

no. this shit makes no sense

[@codestorywithMIK]

Tyrone Slothdrop I totally agree

[@purpleice2343]

Kevin, of course it doesn't make sense when you're braindead xD

[@adityarprasanna]

Came to the comment section to say the same thing and I see I was beat to it.

[@vavilon7109]

I thought that geneticists are terrible at naming things but coders have their share of confusing nomenclature. Despite that, I got it because of this video! Thanks Corey!

[@zsszeli]

Man, this is the first video where I actually get what this means. You are the GOAT, my friend.

[@rukhan8900]

I hope you know that even 6 years after posting your content is still helping beginners like me understand python better than anything else on the internet can! Thank you for your work, it's great! :)

[@kellzbaker]

9 years baby

[@nigthfall345]

hows your coding journey now?

[@kogcyc]

Hi, Corey. If you ever wonder if you're making a difference in the world, then let me assure you that you are. Your videos make learning and using Python possible for those who watch them. Beautiful work. Thank you very much.

[@coreyms]

Thanks!

[@gonzalotoloza6700]

@@coreymsyeah you helped us so much, thank u

[@dc3295]

yeah corey just released so much mental steam in the beginning python world....

[@EV4UTube]

I have found a way of conceptualizing this line of code in a way that (for me) may be easier to understand ... Think of any single individual who is part of a family; we will call this person Xavier. Let's talk about the relative terms we use when relating Xavier to the rest of his family. His parents consider Xavier to be his SON. His sister considers Xavier to be her BROTHER. His second-tier relatives consider Xavier to be their COUSIN. His grandparents consider him to be their GRANDSON. Lastly, Xavier considers Xavier to be HIMSELF. Xavier is still the same person in each of these relative relationships, but the relative term we use for him is different depending on who we are relating to. So, when we write, "If __name__ == __main__" then we are effectively asking is: "If == HIMSELF" If that code evaluates to TRUE, then we know that the program is running on its own - it is referring to itself. == "HIMSELF" If, however, that code evaluates to FALSE, then we know that the program is running as a component of another program. That is, when you run the code "if __name__ == __main__" and it evaluates as FALSE, then it would be **metaphorically** equivalent to the return values being something like the following: == "SON" == "BROTHER" == "COUSIN" == "GRANDSON" In other words, Xavier is not operating as HIMSELF, he is operating in relation to some other entity (a subcomponent of another program).

[@FloppyCuber1993]

this made me confused as hell at the beginning ;) But is a good explanation too.

[@lvplvp]

Wow thank you for the great explanation!!

[@Mr.Jiggle]

it is more like if relative pronoun is not son, brother, etc.. then this is not the main "xavier" it is someone else IMPORTED to this file "family", correct me if im wrong

[@EV4UTube]

@@Mr.Jiggle I dont see a problem with your analogy. However, I also dont see a difference. I feel like you identified a difference with no real distinction. If Xavier is your nephew, he's not your child (you've imported him to your family). But if your approach helps you capture the concept, then run with it.

[@Mr.Jiggle]

@@EV4UTube thanks, i was just making sure that i caught it right, i almost understand rn, thank you again

[@supermanish]

Haven't encountered an explanation as good as this. Thank you! The world needs teachers like you.

[@brandonhunter3036]

The absolute clear and concise explanation I've seen on this in 5 years off and on of playing and working with Python. Well done!

[@nigelmtb]

What everyone else said: best explanation available. Thank you very much.

[@ashishdeora8522]

It's hard to believe that such a complicated concept can be explained like this. Cheers Cory, the great!

[@notanenglishperson9865]

It's not that complicated, it's just terribly explained by others

[@jenniferf.8387]

New to Python, I'm a C# developer, this video was exactly what I needed... just had to find the right one so it would click. THANK YOU!

[@anindam9179]

okay, this person is so nice that he repeated the same thing without sounding repeatative at all. anyway, coming to the point, I think for average,slow,diverted students the video needs to be seen twice or whatever, there's got to be some kind of repeatation; but for focused students he's a great teacher

[@garydunken7934]

I considered "if __name__ == '__main__'' as some magical conditional check that triggered the main function for me, until I watched this video today. It's clear now. Your explanation was so clear and simple it made so much sense. Thanks.

[@AliColak]

THIS MAKES SO MUCH SENSE. I spent an hour and a half today rewatching the video i learned it from and trying to get a grasp on it. Makes a lotta sense when you explain and show it the way you do. It's sort of like a validation prompt to see which file is being run to avoid duplicates etc.

[@humanOSx]

man you are awesome, I started with the first video of Flask series and now I come here for understand the ifmain conditional. thanks for your youtube channel, it will be for very much help, I am a new subscriber, like in all your videos. Greetings from México.

[@crimepunishment5372]

Corey, Man, you are an asset to humanity indeed, keep the good work.

[@potterdkk4371]

I stuck for DAYS on this, THANK YOU SO MUCH for explaining the topic really clearly.

[@qbaloch]

I gone through dozens of explanations but never understood the purpose of _name_ until I found your video... Thanks very much.

[@JRavenell]

This is the best explanation with EXAMPLES I've ever seen on this. This will help me tremendously. I salute you!

[@abu5197]

I've literally been searching for this for the past two years. So simple yet I haven't seen anyone explain it better!

[@4abdoulaye]

Clearest one I ever found and reference my friends.

[@yogiblak7819]

You are quite literally the BEST explainer in the world! You could take any concept and get the most mentally incapable person to understand it. Great job!

[@alfredgarrett9589]

I commend you on your teaching. I struggled with this concept for a long time, now it seems so simple.

[@seancampbell1682]

Man, I was having a tough time understanding this concept. Thank you so much for this excellent explanation!

[@Baba-so6fh]

Finally it makes sense! Great video. So I understand now that the variable __name__ is different depending on whether the Python file is being run directly as a script or if it is imported somewhere else. If someone imports it, you can choose for the contents not to be run.

[@cass12345]

I came here because I was confused by a Udemy course I'm doing - your explanation was fantastic and simple. Thank you.

[@giorgionapoli85]

"So, I really hope this video was useful..." Yes man... yes. Big YES. Damn it, thank you! And it's not the first time you englightened me.

[@pptx704]

I have read a lot of articles on this specific topic, but none of them could make me understand this "if __name__==__main__" thing. Thanks for making it simple and understandable. By far the best one I've come through!

[@LuisMan8]

You say: "Thank for wacht it"... I say : Thank for teach me !!!!

[@sourabhsaini967]

You r right

[@nemplayer1776]

NemCorrect: You say: "Thanks for watching" I say: "Thanks for teaching me!" Always on service.

[@ycombinator765]

@@nemplayer1776 you did not get the joke!

[@hanle2566]

@@ycombinator765 what is the joke? mind to elaborate?

[@copperymarrow1583]

r/whooosh

[@tahep3906]

this seemingly complex topic can't be explained better that this, thanks a lot for clarifying it...

[@Skypriv]

You rock. I'm so lucky, I looked down out of confusion while watching a tutorial because this was used (but I had no clue what it was).. my eyes just happened to see this video suggested, noice

[@adityapradhan8474]

I was terrified by this concept. But it was so simple. Thank you so much. People don't know how to teach, but you surely do...

[@CuongNguyen-gu9fl]

If you want understand Python more clearly, check the video "What does it take to be an expert in Python" by PyData. It will give you an overview of how Python, specifically the "underscore" methods, works.

[@dwainetrain]

Your clarity is a godsend! Thank you for the instruction Schafer Sensei!

[@gambomaster]

One of the best Python instructor on KZbin. 👍👍👍

[@MrTigerstyle80]

THE MOST cogent explanation of python import machinery available IMHO.

[@BythanProductions]

I spent all morning finishing your OOP walkthrough videos and just ended with this. You, sir, are amazing.

[@codestorywithMIK]

You are the only one whose lecture cleared my concept of __main__ in python. i subscribed to your channel as soon as I understood the concept. thanks. keep uploading.

[@haiderhani1998]

i've been roaming around for two days now. this is by far the best video i found. just subscribed!

[@nelsongg347]

THE best explanation on the subject. Thanks Corey!!

[@chilukanand]

Feels so good when you get to decipher __name__ = '__main__'. For years it was a huge mystery and blindly went with the flow. Thanks for the clarity distinguished mate!

[@JoeEvansSound]

Thank you very much - I have read and read on this subject but was getting totally confused. This video explains things so much better. Thank you very much. Your video is very explanatory and well done. :¬)

[@coreyms]

Thanks. Glad to hear you found it useful!

[@nikhilchigali]

I agree!!! this video clarified my doubts!!

[@Waterlmelon]

This is the best explanation for if __name__ == '__main__' that bothered me every time I saw it in a python code and tried to ignore it and escape from it. Thousand thanks!!

[@jayw.1139]

Sir, you will live 10,000 years!! Thank you for this informative video. Straight and to the point to which I could easily comprehend.

[@abdelhaqfaouzi]

I'm learning Python on my own and haven't reached the underscored 'thingies', but just watching this video, I understood the whole concept!! Thumbs up!! thx

[@lardosian]

Such a joy listening to your tutorials. The instructor in my paid course just keeps stuttering and mumbling to the point where I lose the will to live. You are a life saver, easily in the top 3 instructors online.

[@coreyms]

Thanks! I stutter and mumble a lot as well, but I edit all of that out because I don't want to waste the viewers time. Glad you enjoy the videos!

[@vinhtranphuc715]

Great! You're one of the greatest Python tutor on KZbin

[@ducpham9991]

After three years used python, finally, i know why they use it :)) thanks so much

[@fafza1]

Finally. I had seen that scary double underscore several times and couldn't figure out what it was all about. Thank you for the explanation.

[@zaqwsx28]

KZbin recommendations can apparently read my mind. Thanks for covering this topic!

[@nitishbansal6878]

Finally understood this after 2 years of starting programming!!

[@sephkm7482]

thos was the best and really honestly ever best explanation for this term I've been always trying to understand! Thanks so so much!!

[@aatt3209]

OMG, this is the first time I am getting the concept using __main__, thank you so much for being a great teach!

[@Sheriff.Movement]

Can't get better explanation than this🙏🏼

[@heron22wading]

you can have waaaaaaaaay better explanations than this crap. He just wrote shit and didn’t bother to explain new stuff

[@skull4110]

@@heron22wading fuck off. Writing stuff is exactly what I needed.

[@jparth1593]

Agree

[@AmitParam]

@@dr.rijjaayaz8160 ___

[@AmitParam]

@@dr.rijjaayaz8160 sgs

[@pkavenger9990]

This is the best tutorial so far. This thing is kinda tricky one. Sometimes i understand it but when someone ask me to make them understand, i start thinking maybe i did not get the concept, i have to check again.

[@ytb93holmes]

Clear conception. And other puzzle is that I'm interested in learning how to execute and preview the result on sublime text after finishing python?

[@dusanbiga4948]

Probably figured out by now but sublime is a texteditor and not a IDLE.

[@NotxarbProd]

CTRL-B

[@MrinmoyHaloi]

Change build system to python3 and then ctrl+b

[@myblurryfaceromance5146]

Tried to understand this from my lecturers for 3 weeks. Understood it from your channel after 6 minutes into the video. TYSM

[@tnmyk_]

This is EPIC! Thanks a lot for making this video!

[@brianontheair]

Holy crap I’ve been looking for a good explanation of this for forever. After not understanding when I first started learning I just skipped past it and always ignored it every time I saw it. But today I decided I was going to sit down and understand it and you made it clear. Thank you.

[@gyan2664]

perfectly explained ..thx a lot confusion removed ...

[@JoeChang-u4v]

Thanks, this is definitely by far the simplest and clearest explanation I've read.

[@1377sv]

brilliant yet concise explanation. ThankYou

[@daniel-u7t9q]

8 years later and it's still useful! Thank you so much for the amazing video :)!

[@raj1307]

I found your explanation best........Thank you so much..!!

[@Moh_ha]

I was really confused the first time I watched the video. now I got it!! thanks man

[@Sabre00]

When I found this out at first I couldn't see the usefulness of it but I realized that I could test my modules separately and not have it called within my main program. Great explanation as always.

[@shahulvkhameed]

No one in this planet can give this much simpler explanation.....hats off to Corey Schafer

[@afrankiuk78]

Great explanation! I completed a graduate program in data science and none of the professors explained this as clearly.

[@abdulraaziq7055]

This guy explains the best...answers all the questions that appears in the mind while watching...keep going

[@tammytreit3877]

Thanks, clear and super helpful to this beginner!

[@board_runner]

Cheers. Finally an explanation that made sense. How others have failed to explain _that_ is beyond my imagination.

[@bhaskartrivedi3114]

2021: These are future-proof tutorials!

[@sbsyr5555]

Superb explanation......👌👌👌 I could have first watched this video instead of searching explanation in stack overflow so that my 30 mins is saved....Thank you very much....

[@pyTechLife]

Finally got this. Thank you a lot!

[@sixadamra]

5 years later this video is still great. Thanks for this explanation, it clears up the concept perfectly.

[@gustavo_yohan]

Very helpfull video , thanks for upload this video

[@simonfelix9138]

Crystal clear and very helpful series of videos. You seem to acutely anticipate areas of confusion for an audience who is looking at the topic with a fresh pair of eyes and then proceed to clarify these doubts with simple but complete explanations and back it up with relevant examples. There are loads of online paid courses that fall far short from the level of your videos. Kudos. Wish someone could teach the hosts of instructors and trainers out there to emulate your capabilities, many of these courses seem to frustrate new students more than help them.

[@rubialugattimoreira1978]

Best explanation! 👏👏

[@easydatascience2508]

See mine too. The channel has Python crash tutorials, and R beginning course tutorials. Step by step, sequentially. And you can download all the source files (can be found in the description of the video).

[@ritikaprasai5118]

You are the best tutor on you tube! Thank you for your wonderful videos. Please add more videos with real world problems.

[@Nonplused]

I'll be watching more of these videos for sure. My 14 year old son is learning to program in Python, but of course in my day Visual Basic was all the thing, so I have a hard time helping him even though I am very good with VB. The syntax is quite a bit different and the way people use Python is also quite a bit different. Even just the fact that logical statements like if, while, for etc. don't need to be terminated but rely on formatting is new to me. No more "end if". Visual Basic is more like Visual Pascal only without dynamic variables. Shows how old I am. And when did we go back to running stuff from the command prompt? It took me an hour to figure out how to get my computer to launch python that way even with the help of a video. Mind you I wasn't very familiar with setting system variables. I also really miss the "Step" debugger function in VB. I found something similar in Python but since half the time you are in imported code I have no idea what it is pointing at. My son would joke "oh look we are at line 1048 of my 50 lines of code". A video on how that works would be great.

[@omergrn5985]

There is no beetter explanation than this video bro Thnx from 5 years later !!!

[@gherbihicham8506]

Coming up from a C++ and Java world I use the "if __name__ == '__main__':" functionality almost religiously, even though most of the time I dont need it.

[@qwerasdfhjkio]

___name___

[@ansariataullah3064]

It was very helpful ,I stuck here for 1 day. Your teaching is in very simple simple way easy to understand by any one.......

[@robodair]

Concise and to the point. Nice :)

[@akira_asahi]

Thank you for the video. I am grateful for your time and contribution. Kind regards, Akira.

[@susarlaaditya5629]

Subscribed: Man you explained very well!

[@ericsteph]

Hats off! you exaplain it simply and clearly. I have always thought this main story was complicated but thanks to you, now I fully grasp it.

[@luijo633]

You just cured my anxiety

[@belacy87]

Great video. I learned Python from a bootcamp which skipped these essential basics. Very helpful !

[@lilJ5754]

Very well explained. When would you actually need to use this though? I am having trouble coming up with a good example..

[@Denis-xl8jx]

The only thing I know if is testing. Define a function and test if it works properly.

[@alpstinger5083]

The guy is a pure genius. Crystal clear explanation.

[@roshanyadav2078]

Thanks Corey this was wonderful!! Just a question when I can use this? Any example from any of your practical programs?

[@nikiffleser2599]

I mean you just use it in every programm (module) for the sake of importing it later on.

[@piyushsharma7585]

So simple, so elegant. Loved the way he explained this. I’m not gonna forget this thing in my entire life. Thank you

[@andrewluo6088]

I am from china my teacher never explain these things to us thank god i have find this video

[@Hephasto]

Andrew Luo do you ask him to explain ?

[@realnice3672]

@@Hephasto maybe he is introvert.

[@lakerman32]

What a great and clear explanation. Really well done and appreciated!

[@dawei9450]

Sorry to raise this rookie's question. In the video you use a method in print as : print 'first is: {}'. format(__name__) After having played with it a bit I found it to be the same with print 'first is: %s' %(__name__) I wonder if there is any difference between them and could you briefly introduce a bit about the advantage (or some tricks) of using "{} and .format"?

[@u.pawanvinayak]

thanks Corey for giving crystal clear explanation for the special variable __name__ moreover while watching this video, i had also doubt regarding print 'first is: {}'. format(__name__) and then while scrolling through the comments i found your reply thanks a lot for this as well..... just a small question here: as you said in the video that __name__ is a special python variable my question is are python special variables are similar to environment variables as those in languages like shell?

[@osgiliath_burns]

The difference is between Python 2.x and 3.x . %s is the string formatter for 2.7 and {} the formatter for 3.x

[@dawei9450]

Thanks a lot. Now I see where does this come from. And just out of curiosity, does Py 3.x completely cancelled the %s, %d, %f expression, or it just replaced the %s with {}?

[@osgiliath_burns]

afaik there are no % formatters in py 3.x

[@dawei9450]

Thanks for the info ~!

[@Nugeorge]

What an excellent explanation -- I finally had that 'eureka!' moment with this topic after my brain failed to comprehend several other tutorials about this.

[@rigid9822]

thanks mate great explanation

[@ramrajecr777]

Bravo 👏🏻 Print "Thanks Corey"