26.Python：文件修改的两种方式

# 方式一：文本编辑器的方式
# with open('a.txt', mode='rt', encoding='utf-8') as f1:
#     res = f1.read()
#     data = res.replace('a1', 'b1')
#
# with open('a.txt', mode='wt', encoding='utf-8') as f2:
#     f2.write(data)

# 方式二
import os

with open('a.txt', mode='rt', encoding='utf-8') as f1, \
     open('b.txt', mode='wt', encoding='utf-8') as f2:
    for line in f1:
        f2.write(line.replace('a1', 'b1'))

os.remove('a.txt')
os.rename('b.txt', 'a.txt')