python学习之老男孩python全栈第九期_day008作业

1. 文件a.txt内容：每一行内容分别为商品名字，价钱，个数，求出本次购物花费的总钱数
apple 10 3
tesla 100000 1
mac 3000 2
lenovo 30000 3
chicken 10 3

sum = 0
with open('a.txt',mode='w',encoding='utf-8') as f:
    f.write('''apple 10 3
tasla 100000 1
mac 3000 2
lenove 30000 3
chicken 10 3''')
with open('a.txt',encoding='utf-8') as read_f:
    for line in read_f.readlines():
        sum += int(line.split(' ')[1])*int(line.split(' ')[2])
print(sum)

2. 修改文件内容，把文件中的alex都替换成SB

import os
with open('a.txt',mode='w',encoding='utf-8') as f:
    f.write('''alex 18
Eva 20
KID 21
kidd 22
alex 38''')
with open('a.txt',encoding='utf-8') as read_f,
    open('aa.txt',mode='w',encoding='utf-8') as write_f:
    for line in read_f.readlines():
        line = line.replace('alex','SB')
        write_f.write(line)
os.remove('a.txt')
os.rename('aa.txt','a.txt')