Python 实现简单的用户注册和登录

#! /usr/bin/env python

db = {}

def newuser():
prompt = 'login desired: '
while True:
name = raw_input(prompt)
if db.has_key(name):
prompt = 'name taken, try another: '
continue
else:
break
pwd = raw_input('passwd: ')
db[name] = pwd

def olduser():
name = raw_input('login: ')
pwd = raw_input('passwd: ')
passwd = db.get(name)
if passwd == pwd:
print 'welcome back', name
else:
print 'login incorrect'

def showmenu():
prompt = """
(N)ew User Login
(E)xisting User Login
(Q)uit
Enter choice: """

done = False
while not done:
chosen = False
while not chosen:
try:
choice = raw_input(prompt).strip()[0].lower()
except (EOFError, KeyboardInterrupt):
choice = 'q'
print '\nYou picked: [%s]' % choice
if choice not in 'neq':
print 'invalid option, try again'
else:
chosen = True

if choice == 'q':
done = True
if choice == 'n':
newuser()
if choice == 'e':
olduser()

if __name__ == '__main__':
showmenu()