文件的修改：

一般是把舊文件的內容改了，在寫入到新的文件中去。

file_old=open("test","r",encoding="utf-8")
file_new=open("test.bak","w",encoding="utf-8")

for line in file_old:
    if "快樂等我享受" in line:
        line=line.replace("快樂等我享受","快樂等HunterYi享受")
        print(line)
    file_new.write(line)
file_old.close()
file_new.close()

with語句的用法。

#!/usr/bin/env python
#-*- coding:utf-8 -*-
# Author:Hunter Yi


with open("test","r",encoding="utf-8") as f ,     open("test.bak","r",encoding="utf-8") as f2: #用with語句 可以同時打開多個文件，用完後自動關閉。

    for line in f:
        print(line)

    for line2 in f2:
        print(line2)

python自學第6天