Check for the prime numbers code and suggest any alternatives

Question

https://code.sololearn.com/cJxJf9Ki5652/?ref=app
Check this one
https://code.sololearn.com/cJxJf9Ki5652/?ref=app

Answer 1

CHITTAMURU NIKHIL
The code looks good, except it's quite inefficient... You shouldn't go through every single number when checking if the number is a prime you should at least go through
sqrt(number) or even
for i in range(3, int(sqrt(i)),2):
(that's the method Coding Cat showed me ;)

So, here is a better way to check if number is a prime:
https://code.sololearn.com/cfO10uzSKk96/?ref=app

Also check out this thread:
https://www.sololearn.com/Discuss/2891515/?ref=app

Answer 2

Looks all good, quite efficient too

Answer 3

A thing to note is that if the number input could be very big, it is worth putting a break in the if clause on line 11, so that it doesn’t take extremely long in the loop, when it is established the number is not prime

Answer 4

This is a little faster and more compact.
https://code.sololearn.com/crkg94t1xKJt/?ref=app

This implements the Primes Sieve of Eratosthenes, which uses more memory but is amazingly fast.
https://code.sololearn.com/clyThoszsdj9/?ref=app