Python includes exercises 14

Python 100 Li

Title: a positive integer decomposition of the quality factor. For example: Enter 90 to print out 90 = 2 * 3 * 3 * 5.

Program analysis: the decomposition of n quality factor, you should first find a smallest prime number k, then according to the following steps:
(1) If the prime number exactly equal to n, then the decomposition of the quality factor of the process has ended, you can print out.
(2) if n <> k, k but n be divisible should print out the value of k, k with n divided by the quotient, you as a new positive integer n, repeat the first step.
(3) if n is not divisible by k, k + 1 is used as the value of k, repeat the first step.

Source Code:

#!/usr/bin/python
# -*- coding: UTF-8 -*-

def reduceNum(n):
    print '{} = '.format(n),
    if not isinstance(n, int) or n <= 0 :
        print '请输入一个正确的数字 !'
        exit(0)
    elif n in [1] :
        print '{}'.format(n)
    while n not in [1] : # 循环保证递归
        for index in xrange(2, n + 1) :
            if n % index == 0:
                n /= index # n 等于 n/index
                if n == 1: 
                    print index 
                else : # index 一定是素数
                    print '{} *'.format(index),
                break
reduceNum(90)
reduceNum(100)

The above example output is:

90 =  2 * 3 * 3 * 5
100 =  2 * 2 * 5 * 5

Python 100 Li