Function greatest_prime_factor

maths/primelib.py:235–271

input: positive integer 'number' >= 0 returns the greatest prime number factor of 'number' >>> greatest_prime_factor(0) 0 >>> greatest_prime_factor(8) 2 >>> greatest_prime_factor(287) 41 >>> greatest_prime_factor(-1) Traceback (most recent call last):

(number)

def greatest_prime_factor(number):
    """
    input: positive integer 'number' >= 0
    returns the greatest prime number factor of 'number'

    >>> greatest_prime_factor(0)
    0
    >>> greatest_prime_factor(8)
    2
    >>> greatest_prime_factor(287)
    41
    >>> greatest_prime_factor(-1)
    Traceback (most recent call last):
        ...
    AssertionError: 'number' must been an int and >= 0
    >>> greatest_prime_factor("test")
    Traceback (most recent call last):
        ...
    AssertionError: 'number' must been an int and >= 0
    """

    # precondition
    assert isinstance(number, int) and (number >= 0), (
        "'number' must been an int and >= 0"
    )

    ans = 0

    # prime factorization of 'number'
    prime_factors = prime_factorization(number)

    ans = max(prime_factors)

    # precondition
    assert isinstance(ans, int), "'ans' must been from type int"

    return ans


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