Python recursive program to prime factorize a number

Question

I wrote the following program to prime factorize a number:

import math
def prime_factorize(x,li=[]):
    until = int(math.sqrt(x))+1
    for i in xrange(2,until)         


        

Answer 1

If you want to do it completely recursive, I'd recommend this code, it does return the correct answer and the way it works is pretty clear. If you want to make the program as efficient as possible I'd recommend you to stick to one of your previous methods.

def primeFact (i, f):
    if i < f:
        return []
    if i % f == 0:
        return [f] + primeFact (i / f, 2)
    return primeFact (i, f + 1)

This is a completely recursive way of solving your problem

>>> primeFact (300, 2)
[2, 2, 3, 5, 5]
>>> primeFact (17, 2)
[17]
>>> primeFact (2310, 2)
[2, 3, 5, 7, 11]