python分解质因数

# !/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:Hiuhung Wan

num = input("请输入一个合数：")
if num.isdigit():
    num = int(num)
else:
    print("输入非法，请输入一个合数")
    exit()

if num < 2:
    print("请输入一个大于2的合数")
    exit()

def isZhishu(num):  # 判断是否是质数
    for i in range(2, num):
        if num % i == 0:  # 不是质数
            return False
    else:
        return True

l0 = []
def fenjie(num):
    i = 2
    while i < num + 1:
        if num % i == 0:
            l0.append(i)
            num /= i
        else:
            i += 1


if not isZhishu(num):
    fenjie(num)
    str0 = ‘‘
    for i in l0:
        str0 = str0 + str(i) + "*"
    str0 = str0[:-1]  # 去掉最后一个星号
    print("%s=%s" % (num, str0))
else:
    print("%s是一个质数，请输入一个合数" %num)