Python程序设计（三 流程结构）——3.3 while、for循环嵌套

3.3.1 while嵌套的格式

 while 条件1:

        条件1满足时，做的事情1
        条件1满足时，做的事情2
        条件1满足时，做的事情3
        ...(省略)...

        while 条件2:
            条件2满足时，做的事情1
            条件2满足时，做的事情2
            条件2满足时，做的事情3
            ...(省略)...

3.3.1 while嵌套的应用

要求：打印如下图形：

    *
    * *
    * * *
    * * * *
    * * * * *

程序如下：

i = 1
while i <= 5:
   j=1
   while j<=i:
      print("*",end='')
      j += 1
   print('\t')
   i += 1

打印九九乘法表

i = 1
while i <= 9:
   j = 1
   while j <= i:
      print("%d * %d = %d  " % (i, j,i*j),end='')
      j = j + 1
   print('\t')
   i = i + 1

运行程序，结果为：

1 * 1 = 1  	
2 * 1 = 2  2 * 2 = 4  	
3 * 1 = 3  3 * 2 = 6  3 * 3 = 9  	
4 * 1 = 4  4 * 2 = 8  4 * 3 = 12  4 * 4 = 16  	
5 * 1 = 5  5 * 2 = 10  5 * 3 = 15  5 * 4 = 20  5 * 5 = 25  	
6 * 1 = 6  6 * 2 = 12  6 * 3 = 18  6 * 4 = 24  6 * 5 = 30  6 * 6 = 36  	
7 * 1 = 7  7 * 2 = 14  7 * 3 = 21  7 * 4 = 28  7 * 5 = 35  7 * 6 = 42  7 * 7 = 49  	
8 * 1 = 8  8 * 2 = 16  8 * 3 = 24  8 * 4 = 32  8 * 5 = 40  8 * 6 = 48  8 * 7 = 56  8 * 8 =   	
9 * 1 = 9  9 * 2 = 18  9 * 3 = 27  9 * 4 = 36  9 * 5 = 45  9 * 6 =   9 * 7 = 63  9 * 8 = 72  9 * 9 = 81  	

3.3.3for循环嵌套

for i in range(1, 10):
    for j in range(1, i+1):
        print('{}x{}={}\t'.format(j, i, i*j), end='')
    print()

运行程序，结果如下：

1x1=1	
1x2=2	2x2=4	
1x3=3	2x3=6	3x3=9	
1x4=4	2x4=8	3x4=12	4x4=16	
1x5=5	2x5=10	3x5=15	4x5=20	5x5=25	
1x6=6	2x6=12	3x6=18	4x6=24	5x6=30	6x6=36	
1x7=7	2x7=14	3x7=21	4x7=28	5x7=35	6x7=42	7x7=49	
1x8=8	2x8=16	3x8=24	4x8=32	5x8=40	6x8=48	7x8=56	8x8=	
1x9=9	2x9=18	3x9=27	4x9=36	5x9=45	6x9=	7x9=63	8x9=72	9x9=81