3-17作业

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 file(src_fiule, old_content, new_content): with open(r'{}'.format(src_fiule), 'rb') as rf,\ open(r'{}.swap'.format(src_fiule), 'wb') as wf: while True: res = rf.readline().decode('utf-8') if old_content in res: data = res.replace('{}'.format(old_content), '{}'.format(new_content)) wf.write(bytes('{}'.format(data), encoding='utf-8')) else: wf.write(bytes('{}'.format(res), encoding='utf-8')) if len(res) == 0: break os.remove(r'{}'.format(src_fiule)) os.rename('{}.swap'.format(src_fiule), '{}'.format(src_fiule)) return '修改成功' if __name__ == '__main__': inp_src = input("请输入文件路径：").strip() old_content = input("请输入要修改的内容：").strip() new_content = input("请输入修改后的内容：").strip() if inp_src and old_content and new_content: msg = file(inp_src, old_content, new_content) print(msg) else: print("修改失败")

2、编写tail工具

import time
def tail():
    with open("log.txt","rb") as f:
        f.seek(0,2)
        while True:
            new_msg = f.readline()
            if len(new_msg)==0:
                time.sleep(1)
            else:
                print(new_msg.decode("utf-8"))
tail()

#另一个文件
def write_log():
    with open("log.txt","a",encoding="utf-8") as f:
        msg = input("请输入日志内容")
        f.write(f"\n{msg}")
write_log()

3、编写登录功能

def login(inp_u, inp_p): with open(r'db.txt', 'rt', encoding='utf-8') as f: for line in f: user, pwd = line.strip().split(':') if inp_u == user and inp_p == pwd: print("登录成功") break else: print("用户名密码错误") if __name__ == '__main__': inp_u = input("用户名：").strip() inp_p = input("密码：").strip() login(inp_u, inp_p)

4、编写注册功能

def register(inp_u, inp_p): with open(r'db.txt', 'a+t', encoding='utf-8') as f: f.seek(0, 0) for line in f: user, *_ = line.strip().split(':') if inp_u == user: print("用户名已存在") break else: f.write('{}:{}\n'.format(inp_u, inp_p)) if __name__ == '__main__': inp_u = input("用户名：").strip() inp_p = input("密码：").strip() register(inp_u, inp_p)

5、编写用户认证功能

def login(): inp_u = input("用户名：").strip() inp_p = input("密码：").strip() with open(r'db.txt', 'rt', encoding='utf-8') as f: for line in f: user, pwd = line.strip().split(':') if inp_u == user and inp_p == pwd: print("登录成功") return True else: print("用户名密码错误") return False def check_user(user_check): if user_check: print("有趣的功能") else: print("请先登录") def main(): user_check = False msg = """ 1、登录 2、有趣的功能 """ tag = True dic = { '1': True, '2': False } while tag: print(msg) num = input("请输入编号：").strip() if not num.isdigit() and num not in dic: print("必须输入指定编号") else: if dic[num]: user_check = login() else: check_user(user_check) if __name__ == '__main__': main()