primer factor

main.py

# Prime Factorization -
# Have the user enter a number and
# find all Prime Factors (if there are any) and display them.

# primer factors:
# table https://en.wikipedia.org/wiki/Table_of_prime_factors

def prime_factor(n):
  if n == 1:
    return [1]
  factor = []

  def factorization(x):
    """
    将 x 因式分解,
    :param x:
    :return:
    """
    i = 2
    while x % i != 0:
      i += 1
      if i >= x:
        return None, x
    else:
      return i, int(x / i)

  rest = n
  while True:
    fac, rest = factorization(rest)
    if fac is not None:
      factor.append(fac)
    else:
      factor.append(rest)
      break;

  # 如果返回 list 中含有 1, remove 掉
  if 1 in factor: factor.remove(1)
  return list(set(factor))


def shell():
  while True:
    print(">>> ", end='')
    entry = input()
    if entry == "quit":
      break
    if not entry.isdigit():
      print("You did not enter a number. Try again")
    else:
      print(prime_factor(int(entry)))

if __name__ == '__main__':
  shell()