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improved prime_check in math modules #6044

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Merged
merged 6 commits into from
Jul 11, 2022
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improved prime_check in math modules #6044

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8646be9
improved prime_check
Lakshmikanth2001 Mar 11, 2022
dec573e
updating DIRECTORY.md
Mar 11, 2022
4171388
included suggested changes
Lakshmikanth2001 Apr 4, 2022
89095b8
Merge branch 'master' of https://github.com/Lakshmikanth2001/Python
Lakshmikanth2001 Apr 4, 2022
93e5ece
Merge branch 'master' of https://github.com/TheAlgorithms/Python into…
Lakshmikanth2001 Jul 10, 2022
a69345f
updating DIRECTORY.md
Jul 10, 2022
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1 change: 1 addition & 0 deletions DIRECTORY.md
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Expand Up @@ -529,6 +529,7 @@
* [Perfect Square](https://github.com/TheAlgorithms/Python/blob/master/maths/perfect_square.py)
* [Persistence](https://github.com/TheAlgorithms/Python/blob/master/maths/persistence.py)
* [Pi Monte Carlo Estimation](https://github.com/TheAlgorithms/Python/blob/master/maths/pi_monte_carlo_estimation.py)
* [Points Are Collinear 3D](https://github.com/TheAlgorithms/Python/blob/master/maths/points_are_collinear_3d.py)
* [Pollard Rho](https://github.com/TheAlgorithms/Python/blob/master/maths/pollard_rho.py)
* [Polynomial Evaluation](https://github.com/TheAlgorithms/Python/blob/master/maths/polynomial_evaluation.py)
* [Power Using Recursion](https://github.com/TheAlgorithms/Python/blob/master/maths/power_using_recursion.py)
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11 changes: 7 additions & 4 deletions maths/prime_check.py
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Expand Up @@ -32,12 +32,15 @@ def prime_check(number: int) -> bool:
if 1 < number < 4:
# 2 and 3 are primes
return True
elif number < 2 or not number % 2:
# Negatives, 0, 1 and all even numbers are not primes
elif number < 2 or not number % 2 or number % 3 == 0:
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Suggested change
elif number < 2 or not number % 2 or number % 3 == 0:
elif number < 2 or number % 2 == 0 or number % 3 == 0:

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What about numbers like 25, 35, 65 etc ?

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@Lakshmikanth2001 Lakshmikanth2001 Apr 4, 2022 •
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Those numbers are divisible by 5 6k-1 we are starting our loop with 5

# Negatives, 0, 1, all even numbers, all multiples of 3 are not primes
return False

odd_numbers = range(3, int(math.sqrt(number) + 1), 2)
return not any(not number % i for i in odd_numbers)
# All primes number are in format of 6k +/- 1
for i in range(5, int(math.sqrt(number) + 1), 6):
if number % i == 0 or number % (i + 2) == 0:
return False
return True


class Test(unittest.TestCase):
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