python学习日记（文件操作练习题）

name = input('请注册姓名：')
password = input('请注册密码：')
with open('log',mode='w',encoding='utf-8') as f:
f.write('{}\n{}'.format(name,password))#格式化输出，两个参数写进一行，write不允许两个变量
print('注册成功')
lis = []
count = 3
while count > 0:
count -= 1
with open('log', mode='r+', encoding='utf-8') as f1:
for i in f1:
lis.append(i)#读取内容写入到列表中
name1 = input('请输入登录用户名：')
if name1 == lis[0].strip():#strip()可以去除\n,\t
password1 = input('请输入登录密码：')
if password1 == lis[1]:
print('\n登录成功！')
break
else:
print('密码错误')
print('您还有%d次机会'%(count))
if count == 0:
chance = input('机会已用完，是否还想继续？Y(case-sensitive)')
if chance.upper() == 'Y':
count = 3
continue
else:
print('用户名错误，请重新输入')
print('您还有%d次机会'%(count))
if count == 0:
chance = input('机会已用完，是否还想继续？Y(case-sensitive)')
if chance.upper() == 'Y':
count = 3
continue
else:
print('\n明天再来吧')

题目

with open('a.txt','r+',encoding='utf-8') as f:
li = []
li1 = []
for line in f:
li.append(line.split())
print(li)
# dic = {}#问题在这里,dic只有一个地址（自己遇到的问题 1），最后字典里只有一组值，列表里添加的全都是这一组，内存指向问题
j = 0
sum = 0
while j < len(li):
dic = {}#解决问题：每次循环都重新建一个新的dic
dic['name'] = li[j][0]
dic['price'] = li[j][1]
dic['amount'] = li[j][2]
print(dic)
li1.append(dic)#直接添加字典，必须每次循环都要重新定义字典，另开内存地址，不然一直指向同一个地址，列表添加多少次值都是字典最后更新的数据
# li1.append({'name':li[j][0],'price':li[j][1],'amount':li[j][2]})
cost = int(li[j][1]) * int(li[j][2])#不转成int 不能进行运算str
# cost = int(dic['price']) * int(dic['amount'])#不转成int 不能进行运算str（自己遇到的问题2）
print(cost)
sum += cost
j = j+1
print(li1)
print('总的价格为：',sum)#+加号拼接提示int 和 str不能拼接，所以用逗号。（自己遇到的问题3）

with open('a.txt','r+',encoding='utf-8') as f:
li = []
li1 = []
for line in f:
li.append(line.split())
print(li)
# dic = {}
j = 0
sum = 0
while j < len(li):
dic = {}#看到没？放这里啦，关注点一
dic['name'] = li[j][0]
dic['price'] = li[j][1]
dic['amount'] = li[j][2]
print(dic)
# li1.append(dic)
li1.append({'name':li[j][0],'price':li[j][1],'amount':li[j][2]})#从列表添加value，关注点二
# cost = int(li[j][1]) * int(li[j][2])#不转成int 不能进行运算str
cost = int(dic['price']) * int(dic['amount'])#不转成int 不能进行运算str
print(cost)
sum += cost
j = j+1
print(li1)
print('总的价格为：',sum)#+加号拼接提示int 和 str不能拼接，所以用逗号。

with open('file','r+',encoding='utf-8') as f1,\
open('file.bak','a',encoding='utf-8') as f2:
for line in f1:
if 'tony' in line:
line = line.replace('tony','IM')
f2.write(line)
import os
os.remove('file')
os.rename('file.bak','file')