作业9

作业9

1、编写文件修改功能，调用函数时，传入三个参数（修改的文件路径，要修改的内容，修改后的内容）既可完成文件的修改

import os

def swap(path, old_str, new_str):
    """
    swap是修改文件内字符串
    path为修改的文件的路径,
    old_str为要修改的部分
    new_str为修改后的部分
    """
    with open(r"{}".format(path), mode="r", encoding="utf-8") as f1, \
            open(r"{}.swap".format(path), mode="w", encoding="utf-8") as f2:
        for line in f1:
            new_line = line.replace(old_str, new_str)
            f2.write(new_line)
    os.remove(r"{}".format(path))
    os.rename(r"{}.swap".format(path), r"{}".format(path))

swap(r"D:\工具\python\python代码练习\day13\课程代码.py", "示范", "演示")

2、编写tail工具

import time
def tail(path):
    """
    函数用来动态显示新增行内容
    path为文件路径
    """
    with open(path,mode="rb") as f1:
        f1.seek(0,2)
        while 1:
            res = f1.readline()
            if res == b"":
                time.sleep(1)
            else:
                print(res.decode("utf-8"))

tail(r"D:\工具\python\python代码练习\day13\a.txt")

3、编写登录功能,编写用户认证功能

import os
# 编写登录功能
def login():
    inp_user = input("请输入用户名:")
    with open('user_info.txt', mode="r", encoding="utf-8") as f, \
            open("user_info.txt_copy", mode="w", encoding="utf-8") as f1:
        for line in f:
            user, password, count = line.strip().split(":")
            if user == inp_user:
                if access(inp_user):
                    for i in range(3):
                        inp_password = input("请输入密码:")
                        if password == inp_password:
                            print("登陆成功")
                            while 1:
                                cmd = input("请输入命令: q退出")
                                if cmd.upper() == "Q":
                                    break
                                else:
                                    print("命令{}正在执行".format(cmd))
                            break
                        else:
                            count = int(count)
                            count += 1
                            if count == 3:
                                print("该账号已锁定")
                                break
                            count = str(count)
                else:
                    print("该账号已锁定")
            f1.write("{}:{}:{}\n".format(user, password, count))
    os.remove("user_info.txt")
    os.rename("user_info.txt_copy", "user_info.txt")
# 编写用户认证功能
def access(inp_user):
    with open("user_info.txt", mode="r", encoding="utf-8") as f:
        for line in f:
            user, password, count = line.strip().split(":")
            if inp_user == user:
                if int(count) >= 3:
                    return 0
                else:
                    return 1


login()

4、编写注册功能

def logon():
    inp_user = input("请输入用户名:")
    with open("user_info.txt",mode="r",encoding="utf-8") as f:
        for line in f:
            user, password, count = line.strip().split(":")
            if user == inp_user:
                print("用户名已存在")
                break
        else:
            inp_password = input("请输入密码:")
            with open("user_info.txt", mode="a", encoding="utf-8") as f1:
                f1.write("{}:{}:{}\n".format(inp_user,inp_password,0))
            print("注册成功")

logon()

# 选做题：编写ATM程序实现下述功能，数据来源于文件db.txt
# 1、充值功能：用户输入充值钱数，db.txt中该账号钱数完成修改
# 2、转账功能：用户A向用户B转账1000元，db.txt中完成用户A账号减钱，
#    用户B账号加钱
# 3、提现功能：用户输入提现金额，db.txt中该账号钱数减少
# 4、查询余额功能：输入账号查询余额

https://www.cnblogs.com/achai222/p/12513733.html


# 选做题中的选做题：登录功能
# 用户登录成功后，内存中记录下该状态，
# 上述功能以当前登录状态为准，必须先登录才能操作
https://www.cnblogs.com/achai222/p/12513733.html