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

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

2. 修改文件内容，把文件中的alex都替换成SB

 1 import os
 2 with open('a.txt',mode='w',encoding='utf-8') as f:
 3     f.write('''alex 18
 4 Eva 20
 5 KID 21
 6 kidd 22
 7 alex 38''')
 8 with open('a.txt',encoding='utf-8') as read_f,\
 9     open('aa.txt',mode='w',encoding='utf-8') as write_f:
10     for line in read_f.readlines():
11         line = line.replace('alex','SB')
12         write_f.write(line)
13 os.remove('a.txt')
14 os.rename('aa.txt','a.txt')