Python/data_structures/hashing/number_theory/prime_numbers.py
Christian Clauss 64543faa98
Make some ruff fixes (#8154)
* Make some ruff fixes

* Undo manual fix

* Undo manual fix

* Updates from ruff=0.0.251
2023-03-01 17:23:33 +01:00

60 lines
1.3 KiB
Python

#!/usr/bin/env python3
"""
module to operations with prime numbers
"""
import math
def is_prime(number: int) -> bool:
"""Checks to see if a number is a prime in O(sqrt(n)).
A number is prime if it has exactly two factors: 1 and itself.
>>> is_prime(0)
False
>>> is_prime(1)
False
>>> is_prime(2)
True
>>> is_prime(3)
True
>>> is_prime(27)
False
>>> is_prime(87)
False
>>> is_prime(563)
True
>>> is_prime(2999)
True
>>> is_prime(67483)
False
"""
# precondition
assert isinstance(number, int) and (
number >= 0
), "'number' must been an int and positive"
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
return False
odd_numbers = range(3, int(math.sqrt(number) + 1), 2)
return not any(not number % i for i in odd_numbers)
def next_prime(value, factor=1, **kwargs):
value = factor * value
first_value_val = value
while not is_prime(value):
value += 1 if not ("desc" in kwargs and kwargs["desc"] is True) else -1
if value == first_value_val:
return next_prime(value + 1, **kwargs)
return value