Euler Project

primes.py

def sieve_up_to(n):
    possible = list(range(2, n+1))
    primes = []
    for i, p in enumerate(possible):
        if p:
            primes.append(p)
            for j in range(i, n-1, p):
                possible[j] = False
    return primes

from math import ceil
from functools import reduce
from operator import add
def factors(num):
    sqrt_num = ceil(num**0.5)
    facts = reduce(add, ([f, num//f] if num % f == 0 else []
                          for f in range(1, sqrt_num)),
                   [])
    if sqrt_num*sqrt_num == num:
        facts.append(sqrt_num)
    return facts

def n_factors(num):
    n_fact = 1
    for f in primes:
        this_n_prime_f = 0
        if num == 1: break
        while num % f == 0:
            #print('f', f)
            num //= f
            this_n_prime_f += 1
        n_fact *= this_n_prime_f + 1
    return n_fact

search.py

from bisect import bisect_left

def sorted_contains(l, list_):
    i = bisect_left(list_, l)
    return i != len(list_) and list_[i] == l