Python 100例（001）

 1 #!/usr/bin/env python
 2 # coding:utf-8
 3 
 4 ‘‘‘有四个数字：1、2、3、4，能组成多少个互不相同且无重复数字的三位数？各是多少？‘‘‘
 5 n = 1
 6 num = [4, 2, 3, 1]
 7 list_num = [i * 100 + j * 10 + k for i in num for j in num for k in num if (i != j) and (j != k) and (i != k)]
 8 print(‘能组成%s个相互不同且无重复的数字的三位数‘ % len(list_num))
 9 print(‘它们分别是%s‘ % list_num)
10 
11 # 按照从小到大排序
12 for i in xrange(len(list_num)):
13     for j in xrange(len(list_num)):
14         if list_num[i] < list_num[j]:
15             list_num[i], list_num[j] = list_num[j], list_num[i]
16 print(‘它们从小到大的顺序是%s‘ % list_num)
17 
18 # 求所有满足要求的三位数之和
19 sum = 0
20 for i in list_num:
21     sum = sum + i
22 print(‘它们的累计求和是%s‘ % sum)
23 
24 sum_0 = 0
25 sum_1 = 0
26 # 求所有偶数和
27 for i in list_num:
28     if i % 2 == 0:
29         sum_0 = sum_0 + i
30 print(‘所有偶数求和是%s‘ % sum_0)
31 
32 # 求所有奇数和
33 for i in list_num:
34     if i % 2 != 0:
35         sum_1 = sum_1 + i
36 print(‘所有偶数求和是%s‘ % sum_1)