python实现用户名密码校验

 # 输入用户名密码
 # 认证成功后显示欢迎信息
 # 连续输错三次后锁定
count = 0
while True:
  #输入用户名密码
  username = input("Username:")
  password = input("Password:")
  #打开用户名密码文件
  f = open('login_true.txt')
  #打开锁定用户名文件
  f4 = open('login_lock.txt')
  #判断输入用户名是否存在于锁定文件中
  for line in f4:
    user_name2 = line.strip()
    if username == user_name2:
      print("username is locked!")
      break
  else:
    #判断用户名密码是否正确
    for line in f:
      str = line.strip()
      str2 = ','
      user_name = str[:str.index(str2)]
      pass_word = str[str.index(str2)+1:]
      # print(user_name, pass_word)
      #用户名密码均正确，打印欢迎信息并清空计数器跳出循环
      if username == user_name and password == pass_word:
        print("welcome " + username)
        count = 0
        break
      #用户名正确，密码错误，打印提示信息，计数器加1，并判断计数器是否到3
      elif username == user_name and password != pass_word:
        print("wrong password!")
        count += 1
        print(count)
        #计数器到达3次，将用户名写入锁定文件中
        if count == 3:
          f2 = open('login_lock.txt', "a+")
          f2.write(username+'\n')
          f2.close()
          count = 0

        break
    else:
      print("please check out your username!")
      count = 0
    f.close()