import sys
input_name=input("input your name:")
f1=open("F:/测试资料/pythonlearn/day1/luckname.txt","r")
lines = f1.readlines()
for line in lines:
    user= line.strip('\n')
    if input_name==user:
        print("账号已锁定...")
        sys.exit()
f2=open("F:/测试资料/pythonlearn/day1/user.txt","r")
lines=f2.readlines()
for line in lines:
    (user,pw)=line.strip('\n').split(',')
    if input_name==user:
        j=0
        while j<3:
            input_pw=input("input your password:")
            
            if input_pw==pw:
                print ("登录成功")
                sys.exit()
            else:
                print("密码不正确")
            j=j+1
        else:
                
            f1=open("F:/测试资料/pythonlearn/day1/luckname.txt","a")
            f1.write(input_name + '\n')
            print("账号已锁定")
            sys.exit()
    else:
        continue
else:
    print ("账号不存在")    
f1.close()                                                   #关闭LOCK文件
f2.close()


1.while else ,for else,if else
2.关闭系统sys.exit()  
3.读写文件