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')