Normal vs Python devs Checking Primes...

[@rowandevving]

when the python code looks more like nonsense than c

[@mr.k8660]

yh the string looked like haskel or something

[@miteshranjanpanda1776]

​@@mr.k8660 regex

[@yante7]

me when regex

[@vaisakh_km]

@@mr.k8660 the string is regex.... which is as bad as haskel...

[@csolisr]

I know that regex is powerful, but today I learned there's a regex to determine if a number is prime, dear lord that's needlessly clever

[@s.hariharan6958]

i solved some problem using regex in javascript in free code camp that was so fun 😅 with no sence of thinking logics ..

[@GSBarlev]

I found an explanation for it on Stack Exchange. Mind-blowing.

[@no_name4796]

^(2|3|5|7|11|13|17|19|23|29|31|37|41|43|47|53|59|61|67|71|73|79|83|89|97)$ This regex matches only primes under 100 ;-)

[@Edouard.Choiniere]

In the C version, you don’t have to check up to n/2. You only have to check up to sqrt(n), or the last integer number of sqrt(n) (floor).

[@mrfli24]

yup. If it's composite, it must be a multiplier of some number up to sqrt(n).

[@xarkenz]

an easy way I've found to do this while avoiding a square root is just having the for loop condition be "i * i 0) return false;" inside the loop and "return true;" after the loop 😭

[@Edouard.Choiniere]

@@xarkenz Im not sure that doing i*i n times in the loop is really better than computing a sqrt once, out of the loop. Not only overhead, but numbers will get big at a point. Im sure there are some ways that completely avoiding floating points are needed, like in some specific embedded scenarios

[@xarkenz]

@@Edouard.Choiniere ooh, i didn't think about that. i guess in terms of complexity, i think sqrt is O(1) and multiplication is O(n). and about the numbers getting big... i think the only time an overflow could occur is when (i-1)*(i-1)

[@jhgvvetyjj6589]

And by using long long instead of int, the 131234747345 will even work

[@martingeorgiev999]

a c dev would never do it so inefficiently

[@truebender]

pathetic. as one of the c++ devs, I can just simply make a header file

[@azeek]

nodejs: proceeds to install whole universe before doing anything

[@norielgames4765]

Now check how fast both are and how much memory they use.

[@vaisakh_km]

why should? lets be real... 99% projects out there only going to used by max 1000 people who don't see difference of 0.1 sec and 0.001 sec or 1mb vs 10 mb edit: you were taking this algorithm taking up too much memory and not a blew at python..? i agree with you...

[@Faunarr]

@@vaisakh_km Considering that prime numbers mainly have a scientific application, then yes that matters quite a lot. And if you just want to check for primes you can just google it and you get your result instantly.

[@eig5203]

the python solution was more like a regex solution...

[@bryceblazegamingyt9741]

​​@@vaisakh_km bc python sucks by a much larger margin than a millisecond. Also 0.1 is literally ten times slower than 0.001 seconds so your point makes no sense

[@vaisakh_km]

@@bryceblazegamingyt9741 ok, i won't write a rendering engine using python, but to parse some csv to json, it's more than enough... anyone can wait a min for it

[@kienha9036]

I thought the joke was having the Python version importing C one

[@ENNEN420]

And here I thought python was supposed to be MORE readable than C. I guess C chads can't stop winning

[@xWatexx]

There’s regex for telling if a number is Prime? That’s news to me.

[@Dev-Siri]

when c looks easier than python:

[@5cover]

it's not specifically python, you could to this in any language with builtin regex support BUT WHAT THE HELL? A regex to match prime numbers? How?

[@KanashimiMusic]

It doesn't actually match the number, it makes a string that is N characters long and checks if it can split the string into at least two substrings of equal length

[@diobrando7642]

I was flabbergasted, but then I remembered, regular expression have a complexity of O(n) where n is the length of the string they're analyzing. Sadly, even if you used a regular expression in C, the first program would have been more efficient nonetheless, since it has to iterate just sqrt(n) times (not n/2)

[@velox__]

Not all regex engines have guaranteed O(n) complexity.

[@diobrando7642]

@@velox__ it's an approximation, but all regular expressions can be implemented as finite state automata, so it's generally O(n)

[@velox__]

@@diobrando7642 yes, but not all are implemented like that :) I was being padentic anyway

[@KanashimiMusic]

@@diobrando7642 For actual regular expressions, what you're saying would be correct - however, note how this Regex uses a capture group and, more importantly, a back reference. Back references to capture groups require the algorithm to remember something it previously found and match it again, which already isn't possible using finite state automata. Additionally (afaik), it also needs to make several attempts regarding how many characters actually belong into the capture group until the back reference matches. All of this means that the complexity of this is VERY far away from being O(n).

[@diobrando7642]

@@KanashimiMusic thank you for this input, I know regex implementations can differ from theoretical regular expressions, I just wanted to say that in the best case (so considering a regular expression which is implemented with a finite state Automata) that would still be O(n) vs O(√n) (I could have worded it better)

[@slava6105]

I thought my world broke on "check divisibility by 7" with regex. Now my world is falling apart with "check if prime with regex".

[@SuperQuwertz]

Really cool video, I like the style! :D

[@blaze_arch6864]

Awesomee video, Virbox! ^_^ C is best programming language ever 😎

[@Ne-vc5pm]

No dependency manager? Zero safety? No bches?😢😢

[@blaze_arch6864]

@@Ne-vc5pm Yes. 😎

[@truebender]

​@@Ne-vc5pmvalgrind.

[@giuyo]

C++ is better than C tho

[@nevokrien95]

Never ever saw this type of python code

[@brawldude2656]

Just write a regex that covers all composite numbers... I see no problem with that

[@flamakespark]

clearly a fake comparison, C program should've ended with SegFault - average Python dev copium

[@adershvarshnei5198]

What font is that on the c version?

[@squid13579]

regex in python looks more dangerous than c.🤣

[@callyral]

did you just use a regex to determine if a number is prime???

[@um8078]

Brother what is that font

[@bundzsi]

As a person who is learning Python at the moment, this made no fucking sense

[@Henry14arsenal2007]

Can anyone explain wtf is happening in the Python version?

[@konstantink07]

look up regex

[@prepareyourpainis]

Drugs, probably

[@santirruki4743]

coding in comic sans:

[@anon-fz2bo]

bro u can solve that with a simple for loop lmao, idt time complexity matters if ur writing it in C, itll still be blazingly fast. ie static const uint8_t is_prime(const unsigned long x) { size_t matches = 0; for (auto i = 1; i

[@lavaquark]

I think you know that this is not how you check if a number is prime

[@Jonas-gm4my]

Can some smart guy explain the regex hack to me?

[@Voidkitty_]

Me dividing the number by every int smaller than its sqrt

[@sayamqazi]

Shouldnt do by every int Only the prime ints

[@Voidkitty_]

@@sayamqazi that's harder to do with every int you can have a variable start at 2 and then add on and then add two and then keep adding two until the variable is greater than the sqrt

[@EntityPlantt]

I love how the title clarifies that Python users aren't normal programmers

[@RetroEcoChicken]

how do you know a coding language is useless? ++ is not recognized.

[@ollicron7397]

Use the simpy module dude.

[@GSBarlev]

Huh. Seems overly complicated. I would have just done: import primelib print(primelib.isprime(n)) (examples of primelib include sympy and primespy)

[@lonelyshpee7873]

The correct way to code in Python is to leave as much as possible up to libraries written in C.

[@mrfli24]

It sounds pythonic to me. Great work. haha.

[@cmaxz817]

Python dev tries not to pass data to libraries written in C challenge (impossible)

[@_kitaes_]

and primelib is written in c lol

[@KanashimiMusic]

Bro it's a joke

[@disconnect3d487]

song>?

[@GSBarlev]

He credits the original songwriter at the end 😉

[@originalnamegoeshere]

C devs are normal now?

[@sdkdoom]

lmao imagine only knowing how to use others libraries and calling yourself a programmer

[@彭煥城-t7r]

The code is really bad

[@EnterOne100]

bool prime = n > 1

[@freerussianman]

def check_prime(number: int): if number % 2 == 0: return True else: return False while 1: value = int(input()) print(check_prime(value))

[@_kitaes_]

check_even*

[@KanashimiMusic]

bro got "even" and "prime" confused wth

[@Razumist-e2g]

​@@KanashimiMusic, default python "programmer"

[@Rallidars]

Дякую за твої відео дуже цікаві та круті

[@Virbox]

приємно чути)

[@ulysseyang9733]

Python is all about library. That's why I like C more.

[@Dr-Zed]

Normal vs Python 😂

[@imaz0mbie_]

linux users when they see 1 byte of bloat: 😡

[@MrAbrazildo]

#include bool is_prime (const int N, const int i) { return i*i > N ? true : (N % i ? is_prime (N, i + 2) : false); } int main ( ) { //Automated tests: #define _(B, N) assert (B == is_prime (N, 3)); assert (N % 2) // Don't test even numbers: 2 is the only 1. _( true, 5); _(true, 13); _(false, 9); _(false, 21); _(true, 11); _(false, 123); _(true, 313); _(false, 909); _( true, 1021);// _(false, 454); _( true, 797); _(false, 9909); return 0;//EXIT_SUCCESS; }

[@moonyl5341]

matt parker did a video on something similar its ^.?$|^(..+?)\1+$

[@gabrielmendietahernandez3320]

return n % 2 == 0

[@KanashimiMusic]

That's even, not prime...