10 Python Comprehensions You SHOULD Be Using

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In this video, I will be showing you 10 Python comprehensions you can & should be using. These comprehensions will progress in difficulty, so be sure to stick around until the end of the video!
If you want to land a developer job: techwithtim.net/dev
⏳ Timestamps ⏳
00:00 | Overview
00:11 | Basic List Comprehensions
02:06 | Comprehension Condition
04:22 | If You're Serious About Becoming A Developer
05:20 | Comprehension With Multiple Conditions
07:42 | Multiple List Comprehension
09:18 | If/Else In A Comprehension
11:22 | Nested List Comprehension
14:32 | Transformation In Comprehension
15:38 | Dictionary Comprehension
16:47 | Set Comprehension
17:49 | Generator Comprehension
Hashtags
#techwithtim
#programming
#python

Опубликовано:

4 июн 2024

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Комментарии : 118

@TechWithTim 2 месяца назад

If you like this style of teaching check out my full software development program: techwithtim.net/dev

@DarinCox-or1iq 2 месяца назад

Job opportunity 🙌 🙏 is the money you have given to many of these people and I will send them some more important information about what you have done ✔️

@satheshasachithra 2 месяца назад

could you do javascript beginner to pro challenges on code wars or anyotherway

@MiAmigoKier 2 месяца назад

May I ask, what is your keyboard, it sounds great btw

@DarinCox-or1iq 2 месяца назад

@gameslp7583 Месяц назад

boy do you know str.startswith() and str.endswith ?

@kerrykreiter445 2 месяца назад

Absolutely the best tutorial I’ve watched on comprehensions. Thank you for making it very understandable. I would also appreciate the same type of video covering Lambda functions. Thanks again for helping so many!!

@whiteedward1 21 день назад

I've barely learned anything in python and easily picked up the information. So simple, yet elegant explanations. Thank you. It has already helped me in my assignments.

@Indently 2 месяца назад

07:28 I actually never knew you could insert multiple conditions like that, pretty cool!

@RadChromeDude 6 дней назад

what's the difference between that and simply chaining the conditions together with the "and" operator?

@andresbonelli 2 месяца назад

You can even nest comprehensions inside of other functions, inside of user inputs... ie: print(*(list("Hello" for _ in range(int(input("How many 'Hello' would you like to print? ")))))) Python is wild...

@mikec64 2 месяца назад

I found the way you formatted the comprehension that calculates squares is a really helpful way to think about comprehensions, even if I compress them to a single line. In that form, it looks like the comprehension just skips the result=[ ] statement, which I always thought was ugly. And in nested loops it gets rid of all those intermediate lists and variables. For the first time they look more elegant to me.

@BiologyIsHot Месяц назад

The syntax for flattening a list always feels very wrong. Given that single list comprehensions put their iterable to the left, it always feels odd that for num in row is to the right of matrix. It REALLY feels like it should have been [num for num in row for row in matrix] instead of what it actually is. I actually think this is one of the worst bits of Python and I encourage people to not do these neste/unpacking list comphrensions because of how unreadable they are. It would have been great if they gave us some kind of unpacking operator syntactic sugar here with [*row for row in matrix]. That would have been a much better syntax than [item for sublist in nested_list for item in sublist]

@eladiomendez8226 2 месяца назад

Is this list comprehensive of all comprehensions ? 😅

@gaussdog 2 месяца назад

Is your comprehension comprehensive?

@YarPirates-vy7iv Месяц назад

As a connoisseur of dad jokes I want to thank you for this contribution. 🎉

@NearLWatson Месяц назад

Comprehensive list of comprehensions to help comprehend a list of comprehensions within which the list comprehension is included.

@ricdelmar4961 2 месяца назад

Another interesting point about generator expressions, is how they work with the all and any functions. Those functions will use the same kind of short-circuit evaluation that compound conditionals use -- that is, they will only evaluate as many items from the generator that they need in order to determine whether the result should be True or False.

@RadChromeDude 6 дней назад

Man list comprehensions are just amazing. I've just finished a level 1000 coding module in python. Basically, i ended up (ab)using list compre wherever I could. It's just that elegant!

@swagatopablo 2 месяца назад

Most comprehensions can be replaced by some combination of map and filter, which I find far cleaner. Further, in most cases, you will iterate through the iterator only once, in which case, you can leave it as an iterator (map and filter) form until you use it (unlike, for example, using comprehension to give you an iterable). This is far more pythonic and memory efficient too.

@elatedbento Месяц назад

Things are a bit gray here. You can easily replace the list comprehension to a generator comprehension by just changing to parenthesis, in case you need that memory efficiency. Most developers nowadays advocate for list/gen comprehensions over map and filter statements, for readability and performance. There is nothing wrong with map and filter, though.

@swagatopablo Месяц назад

@@elatedbento Curious, do most developers advocate against map and filter? Why? I am just curious if there have been some benchmarking on performance or some other motivation behind it that I don't know of. In general, I love the clarity of functional constructs which explains my bias.

@sdmagic 2 месяца назад

Very well done. Thanks!

@lucasseagull8282 2 месяца назад

Man, you grew a lot in past 3 years :)) I'm just watching your video called: Python Selenium Tutorial #2 - Locating Elements From HTML, where you are referring to your website for testing. However, it's no use as the website is now different - can you do the remake of your selenium tutorials / make it up-to date? Thank you and good luck!

@Soyosan22 2 месяца назад

This is an absolutely excellent video. Your examples and explanations are always great. I think it is time for you to start working on a Python book. I am sure it will be a huge success. :)

@mikespon 17 дней назад

I love your teaching style. Very easy to follow. Thank you for all your hard work.

@Ohiostategenerationx 2 месяца назад

Looks good. I'm just now learning it but as far as I can tell it looks way better than the original code.

@DrDeuteron 2 месяца назад

Nested list comp: >>>flattened = list(chain(*matrix)) chain is from itertools.

@jamesarthurkimbell 2 месяца назад

They also have a chain_from_iterable for this case... but I agree, I'd rather just type the star

@kapibara2440 2 месяца назад

Great content, like always from you. Thanks Tim! Greetings from Poland 😊

@user-ty1gv6xg1o Месяц назад

Man... I love how clean this looks

@BruceDuncan Месяц назад

Oof you got me. Been writing python for 15 years and never knew that you could have multiple `if` statements in a comprehension. I have always written `and` and assumed you made a syntax error 😂

@wandksitesupport2777 Месяц назад

nah jit bro got a whole level of python knowledge but still dont know that

@nirty6340 Месяц назад

@@wandksitesupport2777 it doesnt matter to be honest correct me if i wrong but if you replace all if's with and expect first it would work the same

@i5presnt562 Месяц назад

I needed this kind of videos thx so much

@AlexTrusk91 2 месяца назад

Thanks, pretty edutaining stuff

@stefanvanbraam4378 Месяц назад

Hi. Great video. Do you have a video that teaches you how to change the text color (scope) such as print, for, if statements in Sublime 3? Thanks

@user-ts9ks8in2n 2 месяца назад

Comprendre! Thanks Tim.

@AirLight1646 Месяц назад

What a comprehensive guide.

@BrianStDenis-pj1tq 2 месяца назад

Great video. One thing you might add is a speed comparison. I believe comprehensions are extremely fast, and while one might argue readability, performance is far superior.

@GigasAhriman 2 месяца назад

I've always wondered about speed comparison but I have no idea how to set that one up

@BrianStDenis-pj1tq 2 месяца назад

@@GigasAhriman The last example in this video showed a scenario. Star with a range of like 100M. Then make a list of the integers. Do it in a for loop (with list.append()) and then in a comprehension. Use time.perfcounter() before and after.

@GigasAhriman 2 месяца назад

@@BrianStDenis-pj1tq that's the first time I've heard of time.perfcounter() Ty

@BrianStDenis-pj1tq 2 месяца назад

@@GigasAhriman BTW, I left out a character, its time.perf_counter()

@mikec64 2 месяца назад

@@BrianStDenis-pj1tq Thanks for the perf_counter tip. I ran the 3D array (1000 x 200 x 500) test both ways. The loop was 4.7 sec, the comprehension was 2.6 sec. Results varied if I used numbers too small or so large that they ate up all my RAM.

@yasufadhili 2 месяца назад

Thanks alot again

@krzysiekkrzysiek9059 Месяц назад

And these are the best kind of tips 👌

@shapunna6151 Месяц назад

Thanks a lot ❤

@andiglazkov4915 2 месяца назад

Thanks 😊

@dmaynor 2 месяца назад

How does the example at &t6:30 work? you don't have to terminate login in []?

@samoodie 2 месяца назад

Hey tim, i was wondering if you had any videos on your channel that could help me with DSA in python. Do you have like a youtube playlist?

@kazmi401 2 месяца назад

The have a paid course on algoexpert. But that's not for beginners. i have a year of experience. even that's was a little bit hard for me. but now i am smooth. mmmm it was great "i think".

@largewallofbeans9812 Месяц назад

For number 1, it’s much easier just to write list(range(10)) or [*range(10]. Of course, this doesn’t allow for manipulation of the numbers in the range, but it’s still something to be aware of. Same type of thing goes for the conditional comprehension and the filter function.

@user-qs2hn9zp3d 2 месяца назад

tq bro.. I have learned lot. 🥺🥺

@TechWithTim 2 месяца назад

Welcome 😊

@godwinv4838 2 месяца назад

thank you

@nascentnaga 2 месяца назад

I did not know sum() would store the internal value. That is very interesting.

@mahmoudhasan6954 2 месяца назад

You can apply sum(),max(),min(), len() and other functions as well

@KeithKazamaFlick 2 месяца назад

my guy tim. cheers buddy

@chinzorigyou 2 месяца назад

Thanks

@johnsensebe3153 23 дня назад

Instead of [x for x in range(10)], one can simply use list(range(10)).

@jamesarthurkimbell 2 месяца назад

Another benefit is that variables don't leak out the way they do with for loops. Less of an issue if you're using underscores, but still.

@AnatoliyRU Месяц назад

for first `values = list(range(10))` is better

@Da_phuc 2 месяца назад

Ah yeah!! Good stuff aahhhhhhhhh!! More baby boi !!!

@jackiesofir4660 2 месяца назад

This is the only way we populated list where I work. Literly appending is I'll advised

@adiaphoros6842 Месяц назад

The nested list comprehension would be more readable to me if the syntax goes inside out. For example: flattened = [num for num in row in array]

@shawn445 2 месяца назад

This is a great video but I've been having the issue of figuring out when I would use these in real life scenarios m it would be great if I had applicable examples

@DrDeuteron 2 месяца назад

regarding the check on string length (5:40): string[slice(None, 1)] == 'a' and string[slice(None, -2, -1)] == 'y' works so: >>>valid_string = list(filter(lambda string: string[slice(None, 1)] == 'a' and string[slice(None, -2, -1)] == 'y', options)) takes care of business, buy may necessitate a code comment.

@Chill018 14 дней назад

i'm wondering is there a way to use dict comperhensions but not using a list of tuples?

@giovannisins 2 месяца назад

Shouldn't at 5:59 the first condition be greater than or equals to 2 like you show after?

@HarnessedGnat Месяц назад

In the first group the unwanted options are being filtered out, (toss out anything too short), and in the comprehension he is selecting for those strings that match the requirements. Same end result but one test is the inverse.

@giovannisins Месяц назад

You are right, thank you

@svdden_strike 2 месяца назад

Can you teach us how to create a CMS for a website

@mimizone 25 дней назад

note that the implementation with generator that uses less memory, is slower overall

@elatedbento Месяц назад

Comprehension with multiple conditions

@TragicGFuel Месяц назад

Yeah personally, these comprehensions would confuse the hell out of someone who's unfamiliar and probably would have understood the more verbose syntax easier.

@uuuppz День назад

valid_strings = [option for option in options if option[0]!='a' and option[-1]!='y' ]

@tincustefanlucian7495 Месяц назад

nice synthesis. I'm using all of them(except multiple if condition, nice one). I would add another dictionary comprehension that I use often, when i want to filter items or find items in a really big dictionary: hay_dictionary = {"first": 1, "second": 2, "needle":4, "second_needle": 5, "last": 6, .................} a really big dictionary {k:v for k, v in hay_dictionary.items() if "needle" in k} this will return only the item that have in key "needle" {"needle":4, "second_needle": 5}

@Kknewkles 15 дней назад

Is there anything else among features of Python that is on the level of usefulness of comprehensions? I've been programming in Python for over 5 years now, and that's the only half-advanced feature of it that I'm using. Oh, also tiny lambdas and context managers.

@DrDeuteron 2 месяца назад

even/odd. since if is the new goto (harmful), I select with: {0: 'even', 1: 'odd'}[x % 2] which is why devs hate me. Actually, I'd map the list to (2).__rmod__ and map that to dict.getitem.

@gogasaldadze1639 Месяц назад

i would prefer to use this type lis=[i for i in a if i[0]=='a' and i[-1]=='y']

@CynicAtLarge 2 месяца назад

3D example would be more clear if you used different range values for each dimension.

@TechWithTim 2 месяца назад

Good point that was not the best example

@justliberty4072 Месяц назад

I'm surprised that Tim didn't mention the time-performance benefits of using comprehensions.

@erikjohnson9112 Месяц назад

I don't get a generator for your last example: >>> sub_of_squares = sum(x**2 for x in range(100)) >>> type(sub_of_squares)

@JanKowalski-dm5vr Месяц назад

This is generator: sub_of_squares = (x**2 for x in range(100)) and you can use next(sub_of_squares) And this is sum function that call generator instead create whole list sub_of_squares = sum(x**2 for x in range(100))

@lesheq85 Месяц назад

why in 17:42 you got 16 on the first spot and the rest in order? I don't think that was supposed to happen

@garrettsmith315 2 месяца назад

A little heavy on the reverb, could use a tiny bit of bass boost to the voice as well.

@TechWithTim 2 месяца назад

Agree unfortunately my recording setup isn’t the best right now as I’m moving around

@garrettsmith315 2 месяца назад

@@TechWithTim Great content thought...waiting for some Golang.....

@ImmacHn Месяц назад

So basically, sintactic sugar for reduce/map , got it.

@mikeeotool2677 2 месяца назад

TIIIIMMMMM i copy the the script "strings that start with 'a" and end with "y" as it shows in the screen and when i run it give me 3 errors for every instance that you have "string" and asked me for "strings" and the code runned great, so I think you made 3 typos.

@jayamankrah4328 2 месяца назад

Check from your side, it might be you made the typo.

@mbnyc5401 8 дней назад

c# does it so much getter

@Sanjay-tiwary 2 месяца назад

@kazmi401 2 месяца назад

Keyboard name please.

@lamborghinicentenario2497 2 месяца назад

Didn't even know this wizardry existed

@wandksitesupport2777 Месяц назад

i like to watch your video especially in coursecareer im trying to get a job with software engeneer

@Heavy_Lvy 23 часа назад

values = list(range(10))👀👀👀👀👀👀

@timothytjerije7262 2 месяца назад

Good day Tim. Your text is not visible, please find a way. Your lessons are good though...

@TechWithTim 2 месяца назад

Hmmm turn up your resolution

@jeromemoutou9744 2 месяца назад

@@TechWithTim the red text is quite hard to see, especially when highlighted.

@BoredBoy888 Месяц назад

Text is perfectly fine, just find a way to read it 😉

@HarnessedGnat Месяц назад

All text colors look fine on this tablet. Adjust monitor, or try a different one.

@CryptoBuilders 2 месяца назад

is this pythonic?

@newh1ve39 2 месяца назад

I understand the intention… but I dont understand why you dont show the differences in execution time. If there is no difference its not worth it at the moment in my opinion.

@HarnessedGnat Месяц назад

It’s been pointed out in other comments that comprehensions are faster…. Someone suggested Time.perf_counter() Programmers reading code efficiently (see what’s written, faster and more reliably) has value too.

@LiamInviteMelonTeee Месяц назад

I guess this is mostly about readability, the performance increase varies from version to version of python (just got a boost in 3.12, see mcoding's video)