第三周第一次作业

5-8 以特殊方式跟管理员打招呼： 创建一个至少包含5个用户名的列表，且其中一个用户名为‘admin’。想象你要编写代码，在每位用户登录网站后都打印一条问候消息。遍历用户名列表，并向每位用户打印一条问候消息。users = ['admin', 'fafa', 'renji', 'yangshu', 'miemie']
for user in users:
if user == 'admin' :
print ('Hello ' + user + ', would you like '
+'to see a status report?')
else:
print ('Hello ' + user + ', thank you for '
+'logging in again')
结果：

Hello admin, would you like to see a status report?
Hello fafa, thank you for logging in again
Hello renji, thank you for logging in again
Hello yangshu, thank you for logging in again
Hello miemie, thank you for logging in again

5-9 处理没有用户的情形： 在为完成练习5-8编写的程序中，添加一条if语句，检验用户名列表是否为空。users = ['admin', 'fafa', 'renji', 'yangshu', 'miemie']
users = []
if not users :
print ('We need to find some users!')
else:
for user in users:
if user == 'admin' :
print ('Hello ' + user + ', would you like '
+'to see a status report?')
else:
print ('Hello ' + user + ', thank you for '
+'logging in again')
结果：

We need to find some users!

5-11 序数： 序数表示位置，如1st 和2nd。大多数序数都以th结尾，只有1、2和3例外。nums = list(range(1, 10))
for num in nums:
if num == 1 :
print ('1st')
elif num == 2 :
print ('2nd')
elif num == 3 :
print ('3rd')
else :
print (str(num) + 'th')结果：1st
2nd
3rd
4th
5th
6th
7th
8th
9th