1、单条件流程控制

If：

else：

2、多条件的流程控制

If xxx:

print yyy4

elif xxxx：

print yyy3

elif：

print yyy2

else：

print yyy1

eg：修改ex1.py

#!/usr/bin/env python

# _*_ coding = utf-8 _*_

import getpass

name = raw_input('please inputyour username:')

pwd = getpass.getpass('inputyour password:')

print 'the name is:',name

print 'the password is:',pwd

if name == 'huwei' and pwd =='huwei123':

 print 'you login successfully!,welcomehuwei,normal user'

elif name == 'tony' and pwd =='123':

 print 'you login successfully!,welcometony,super user'

elif name == 'humin' and pwd =='123':

 print 'you login successfully!,welcomehumin,superhero user'

else:

 print 'your password is wrong!'

执行结果：

[root@localhost~]# python ex1.py

please input yourusername:huwei

input yourpassword:

the name is:huwei

the password is:huwei123

you loginsuccessfully!,welcome huwei,normal user

[root@localhost~]# python ex1.py

please input yourusername:humin

input yourpassword:

the name is:humin

the password is:123

you loginsuccessfully!,welcome humin,superhero user

[root@localhost~]# vi ex1.py

[root@localhost~]# python ex1.py

please input yourusername:tony  

input yourpassword:

the name is: tony

the password is:123

you loginsuccessfully!,welcome tony,super user

[root@localhost~]#

eg：

变种ex1.py：

import getpass

name = raw_input('please inputyour username:')

pwd =getpass.getpass('password:')

if pwd == '123':

 if name == 'tony':

   print 'tony,normal'

 elif name == 'huwei':

   print 'huwei,super'

 elif name == 'humin':

   print 'humin,superhero'

 else:

   print 'password is wrong!'

else:

 print 'password is wrong!'

执行结果：

[root@localhost~]# python ex1.py

please input yourusername:huwei

input yourpassword:

the name is:huwei

the password is:huwei123

you loginsuccessfully!,welcome huwei,normal user

[root@localhost~]# python ex1.py

please input yourusername:humin

input yourpassword:

the name is:humin

the password is:123

you loginsuccessfully!,welcome humin,superhero user

[root@localhost~]# vi ex1.py

[root@localhost~]# python ex1.py

please input yourusername:tony  

input yourpassword:

the name is: tony

the password is:123

you loginsuccessfully!,welcome tony,super user

[root@localhost~]#

注：

1.冒号是条件控制的结束

2.同级缩进要一致：IndentationError2