简单的登录功能(文本操作、字典、列表使用、if判断、for、while循环、else使用)

#!/usr/bin/env python
# -*- coding:utf8 -*-
import os
catalogue = os.getcwd()#获取当先工作目录,返回当前工作目录路径
#print(catalogue)
isExists = os.path.exists(catalogue+"\\user")#判断目录是否存在
#print(isExists)
if not isExists:#如果目录不存在
    os.mkdir(catalogue+"\\user")#在当前工作目录下创建一个user的目录

userini = os.path.exists(catalogue + "\\user\\user.ini")#判断文件是否存在,exists可多用
if not userini:
    f = open(catalogue + "\\user\\user.ini","w")#打开文件
    f.close()#关闭文件

ban = os.path.exists(catalogue + "\\user\\ban.ini")
if not ban:
    b = open(catalogue + "\\user\\ban.ini", "w")  # 打开文件
    b.close()  # 关闭文件
txt = """
1、输入1注册用户
2、输入2登录用户
3、输入3更改密码
4、输入4删除用户
5、输入5退出程序
"""
f_content = open(catalogue + "\\user\\user.ini", "r")
b_content = open(catalogue + "\\user\\ban.ini", "r")

dict_f_txt = dict()

f_txt = f_content.read()
b_txt = b_content.read()

for i in f_txt.splitlines():
    a = i.split(sep = ",")
    dict_f_txt[a[0]]=a[1]

for i in dict_f_txt.items():
    print(i[0])


while True:
    print(txt)
    content = input("请输入相应指令:")
    if content == "1":
        username = input("username:")
        if username not in dict_f_txt.keys():
            password = input("password:")
            f_write = open(catalogue + "\\user\\user.ini", "a")#a表示在文本末尾写入,r表示写入文本并覆盖之前的内容
            f_write.write(username+","+password+"\n")
            f_write.close()
            dict_f_txt[username] = password
            print("注册成功")
        else:
            print("用户已存在!")
            continue


    elif content =="2":
        username = input("username:")
        if username not in dict_f_txt.keys():#所有字典中的键值
            print("用户不存在!")
            continue
        elif username in b_txt:
            print("用户已禁止!")
            continue
        else:
            for i in range(3):
                password = input("password:")
                if dict_f_txt[username] == password:#判断键是否等于键值
                    print("登录成功!")
                    break
                print("输入错误!",end = "丨")
            else:
                b_write = open(catalogue + "\\user\\ban.ini", "a")
                b_write.write(username + "\n")
                b_write.close()
                b_txt += username
            continue

    elif content =="3":
        username = input("username:")
        if username not in dict_f_txt.keys():#所有字典中的键值
            print("用户不存在!")
            continue
        elif username in b_txt:
            print("用户已禁止!")
            continue
        else:
            for i in range(3):
                password = input("old_password:")
                if dict_f_txt[username] == password:#判断键是否等于键值
                    new_pass = input("new_password:")
                    dict_f_txt[username] = new_pass
                    for i in dict_f_txt.items():#返回字典所有项目(键及键值)
                        f_write = open(catalogue + "\\user\\user.ini", "a")
                        f_write.write(i[0] + "," + i[1] + "\n")
                        f_write.close()
                        print("更改完成!")
                        break
                    break
                else:
                    print("输入错误!", end="丨")
            else:
                b_write = open(catalogue + "\\user\\ban.ini", "a")
                b_write.write(username + "\n")
                b_write.close()
                b_txt += username
            continue


    elif content =="4":
        username = input("username:")
        if username not in dict_f_txt.keys():#所有字典中的键值
            print("用户不存在!")
            continue
        elif username in b_txt:
            print("用户已禁止!")
            continue
        else:
            for i in range(3):
                password = input("password:")
                if dict_f_txt[username] == password:#判断键是否等于键值
                    del dict_f_txt[username]
                    for i in dict_f_txt.items():#返回字典所有项目(键及键值)
                        f_write = open(catalogue + "\\user\\user.ini", "a")
                        f_write.write(i[0] + "," + i[1] + "\n")
                        f_write.close()
                        print("删除成功!")
                        break
                    break
                else:
                    print("输入错误!", end="丨")
            else:
                b_write = open(catalogue + "\\user\\ban.ini", "a")
                b_write.write(username + "\n")
                b_write.close()
                b_txt += username
            continue
    elif content =="5":
        break
    else:
        print("输入错误!")
        continue

包含内容:文本操作、字典使用、列表使用