python学习13——课后练习

# 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 edit_file(file_path,old_c,new_c):
    with open(r'{}'.format(file_path),mode='rb') as f1,\
        open(r'{}.swap'.format(file_path),mode='wb')as f2:
        while True:
            cont= f1.readline().decode('utf-8')
            if old_c in cont:
                newcont =cont.replace(old_c,new_c)
                f2.write(newcont.encode('utf-8'))
            else:
                f2.write(cont.encode('utf-8'))
            if len(cont) == 0:
                break
    os.remove(file_path)
    os.rename('{}.swap'.format(file_path),'{}'.format(file_path))
file_path = input('输入文件路径').strip()
old_c = input('输入要修改的内容')
new_c = input('修改后的内容')
edit_file(file_path,old_c,new_c)
'''
输入文件路径edit.txt
输入要修改的内容好
修改后的内容坏

Process finished with exit code 0
'''
# 2、编写tail工具
import time
def tail(logpath):
    with open(logpath,mode='rb')as tail_f:
        tail_f.seek(0,2)
        while True:
            line = tail_f.readline()
            if line :
                print(line.decode('utf-8'))
            else:
                time.sleep(0.1)
logpath = input('输入监听文件的路径')
tail(logpath)
'''
输入监听文件的路径access.log
12312

sdgfhj

azxcxzh

asdh

'''
# 3、编写登录功能
def login(name,password):
    with open('info.txt','rt',encoding='utf-8') as login_f:
        for line in login_f:
            username,userpsd =line.strip().split(':')
            if name not in username :
                print('用户不存在')
                break
            elif name== username and password ==userpsd:
                print('登陆成功')
                break
            else:
                print('登录失败')
                break
name = input('输入用户名')
password = input('输入密码')
login(name,password)
# 4、编写注册功能
def reg(name,password):
    with open('reg.txt','rt',encoding='utf-8')as f1,\
        open('reg.txt','at',encoding='utf-8')as f2:
        for line in f1:
            username,userpsd=line.strip().split(':')
            if name in username:
                print('用户名已存在')
            else:
                f2.write('{}:{}'.format(name,password))
name = input('输入用户名')
password = input('输入密码')
reg(name,password)