Factorizing a number in Python

Question

Here\'s my code:

def factorize(n):
    sieve = [True] * (n + 1)

    for x in range(2, int(len(sieve) ** 0.5) + 1):
        if sieve[x]: 
            for i i         


        

Answer 1

The Sieve of Eratosthenes helps you find prime numbers below a certain limit. It's not really going to help you with finding the factors of a particular number.

If you want to do that, the simplest approach that I can see is something like this:

def factors(n):
    while n > 1:
        for i in range(2, n + 1):
            if n % i == 0:
                n /= i
                yield i
                break

for factor in factors(360):
    print factor

This basically finds the smallest factor of n (which is guaranteed to be prime), divides n by that number and repeats the process until n is equal to 1.

The output is:

2
2
2
3
3
5

They multiply out to the original number:

>>> from operator import mul
>>> reduce(mul, factors(360))
360