要求，输入name不为空，输入次数最多3次，3次后跳出程序；

知识点：

raw_input

str转int

whil

if elif else continue break

for

导入模块

引用变量值

格式化输出

vim

#!/usr/bin/env python
import sys
user_name = "carson"
this_year = 2014
counter  = 0
while True:if counter < 3:name = raw_input("please input your name:").strip()if len(name) == 0:print "empty name , please input your name again!"continueelif name == user_name:passprint "welcome to login system!"else:print "%s is a not valid user, please try again!" % namecounter = counter + 1continuebreakelse:print "Your input 3 times!"sys.exit()break
age = int(raw_input("How old are you?"))
sex = raw_input("please input your sex:")
hobby = raw_input("Do you hava any hobbies?")
information =  '''Information of company staff Name :%sAge  :%dSex  :%sHobby:%s''' % (name,age,sex,hobby)
print information

输入3次，退出程序！
# python carson.by
please input your name:a
a is a not valid user, please try again!
please input your name:b
b is a not valid user, please try again!
please input your name:c
c is a not valid user, please try again!
Your input 3 times!

输入空白字符，提示一直输入
# python carson.by
please input your name:
empty name , please input your name again!
please input your name:
empty name , please input your name again!
please input your name:
empty name , please input your name again!
please input your name:
empty name , please input your name again!
please input your name:
empty name , please input your name again!
please input your name:
empty name , please input your name again!
please input your name:
empty name , please input your name again!
please input your name:
empty name , please input your name again!
please input your name:
empty name , please input your name again!

输入正确：

please input your name:carson
welcome to login system!
How old are you?23
please input your sex:M
Do you hava any hobbies?football
Information of company staff Name :carsonAge  :23Sex  :MHobby:football

在判断输入次数的还有一种方法是利用for循环：

#!/usr/bin/env python
import sys
user_name = "carson"while True:name = raw_input("please input your name:").strip()if len(name) == 0:print "empty name , please input your name again!"continuefor i range(1,3):name = raw_input("please input your name:").strip()if name == user_name:passprint "welcome to login system!"else:print "%s is a not valid user, please try again!" % namecontinuebreakelse:print "Your input 3 times!"sys.exit()break
age = int(raw_input("How old are you?"))
sex = raw_input("please input your sex:")
hobby = raw_input("Do you hava any hobbies?")
information =  '''Information of company staff Name :%sAge  :%dSex  :%sHobby:%s''' % (name,age,sex,hobby)
print information