range (start, stop, step)
可以只有一个参数：range(5), 是指[0,1,2,3,4]
可以有两个参数：
range(1,5) = [1,2,3,4]
range(-1,5)=[-1,0,1,2,3,4]

while 循环

break 是指退出循环

while True:
    if guess_age==age:
      print ("you are right")
      break
    else:
    ...
    ...

continue 是指退出当次循环

num=1
while num<=10:
    num+=1
    if num%3==0:
        continue
    print (num)

实际输出：

2
4
5
7
8
10
11

while ... : ... else:

num=1
while num<=10:
    num+=1
    if num%3==0:
        continue
    print (num)
else:
    print("this is else statement")

输出：
2
4
5
7
8
10
11
this is else statement

num=1
while num<=10:
    num+=1
    if num%3==0:
        break
    print (num)

输出：

2

作业输出九九表

while num1<=9:
    num2=1
    while num2<=num1:
        print(num2,"*",num1,"=",num1*num2,end= "  ")
        num2+=1
    num1+=1
    print()