Python/project_euler/problem_07/sol2.py
Christian Clauss 1f8a21d727
Tighten up psf/black and flake8 (#2024)
* Tighten up psf/black and flake8

* Fix some tests

* Fix some E741

* Fix some E741

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
2020-05-22 08:10:11 +02:00

70 lines
1.6 KiB
Python

"""
By listing the first six prime numbers:
2, 3, 5, 7, 11, and 13
We can see that the 6th prime is 13. What is the Nth prime number?
"""
def isprime(number):
for i in range(2, int(number ** 0.5) + 1):
if number % i == 0:
return False
return True
def solution(n):
"""Returns the n-th prime number.
>>> solution(6)
13
>>> solution(1)
2
>>> solution(3)
5
>>> solution(20)
71
>>> solution(50)
229
>>> solution(100)
541
>>> solution(3.4)
5
>>> solution(0)
Traceback (most recent call last):
...
ValueError: Parameter n must be greater or equal to one.
>>> solution(-17)
Traceback (most recent call last):
...
ValueError: Parameter n must be greater or equal to one.
>>> solution([])
Traceback (most recent call last):
...
TypeError: Parameter n must be int or passive of cast to int.
>>> solution("asd")
Traceback (most recent call last):
...
TypeError: Parameter n must be int or passive of cast to int.
"""
try:
n = int(n)
except (TypeError, ValueError):
raise TypeError("Parameter n must be int or passive of cast to int.")
if n <= 0:
raise ValueError("Parameter n must be greater or equal to one.")
primes = []
num = 2
while len(primes) < n:
if isprime(num):
primes.append(num)
num += 1
else:
num += 1
return primes[len(primes) - 1]
if __name__ == "__main__":
print(solution(int(input().strip())))