Python基础：for、while循环

 示例：(break的使用)
    i = 0
    while True:           # True，无限循环
        if i == 9:              #  =9，break强制退出
            break               
        print(i)                #  < 9,打印当前i的值
        i += 1

        i = 0
        while i < 9:
            print(i)
            i += 1
        else:
            print('over?')           # 循环打印i,正常结束后，else输出over?

        print('Yes,it is over...')

        ########下面是加入break#########
        i = 0
        while i < 9:
            print(i)
            i += 1
            if i == 8:
                break                   # = 8的时候跳出循环，打印的i与上面相同
        else:
            print('over?')          # over 不会执行，因为用break跳出循环，不是正常结束

        print('Yes,it is over...')

        ########continue#########
        i = 0
        while i < 9:
            i += 1  
            if i == 8:
                continue               # = 8的时候不执行打印8，直接进入下次循环
            print(i)
        else:
            print('over?')          # over 不会执行，因为用break跳出循环，不是正常结束

        print('Yes,it is over...')

string = 'li hai le wo de ge!'
for i in string:

    if i == " ":                 # 不输出空格，空格时，直接进行下次循环
        continue
    print(i, end = "")

    if i == "!":                    # break结束，不执行else,去掉此句，执行else
        print("\n")
        break

else:
    print('over?')          # for循环正常结束,执行over

print('Yes,it is over...')