python基础练习之99乘法表

while循环

1.

a = 1         #定义初始值
while a: 
    print()    #换行
    b = 1      #定义初始值
    while b:
        m = a * b
        if b >= 10:
            break
        if b <= a:
            print(b,'*',a,'=',m,end='\t')#用制表符分割对齐打印的行
        b += 1
    a += 1
    if a >= 10:
        break

for循环

1. for i in range(1,10):
   for j in range(1,10):
       m = i * j
       print(j,'*',i,'=',m,end='\t')
       if i == j:
           break
   print()

2. for i in range(1,10):
   for j in range(1,10):
       product = i * j
       if j <= i:
   #           if product < 10:
   #                spaces = '  '
   #           else:
   #                spaces = ' '
           spaces = '   ' if product < 10 else '  '   #三元表达式，等同于上面的注释语句
           print(j,'*',i,'=',product,end=spaces)
   print()#输出换行

3. for i in range(1,10): 
   for j in range(1,i+1):#第二层循环可以使用第一层的i变量控制循环
       m = i * j
       print(j,'*',i,'=',m,end='\t')
   print()

4. for i in range(1,10):
   line = ''
   for j in range(1,i+1):
       line += '{}*{}={:<{}}'.format(i,j,i*j,2 if j == 1 else 3)
   print(line)

5. for i in range(1,10):
   for j in range(1,1+i):
       print('{}*{}={:<{}}'.format(i,j,i*j,2 if j == 1 else 3),end='\n' if i == j else '' )

6. for i in range(1,10):
   print((i-1) * '\t',end='')
   for j in range(i,10):   # i <= j < 10
           print('{}*{}={}'.format(i,j,i*j),end='\n' if j == 9 else '\t')