【交作业啦】
ex15.py

# 从sys软件包中取出argv这个特性
from sys import argv

script, filename = argv

txt = open(filename)

print(f"Here is your file {filename}:")
print(txt.read())

txt.close()

print("Type the filename again:")
file_again = input("> ")

txt_again = open(file_again)

print(txt_again.read())

txt_again.close()

【会话】
1 运行ex15.py
2 在python中直接打开文件

PS E:\lpthw> python ex15.py ex15_sample.txt
Here is your file ex15_sample.txt:
This is stuff I typed into a file.
It is really cool stuff.
Lots and lots of fun to have in here.

Type the filename again:
> ex15_sample.txt
This is stuff I typed into a file.
It is really cool stuff.
Lots and lots of fun to have in here.

PS E:\lpthw> python
Python 3.8.0 (tags/v3.8.0:fa919fd, Oct 14 2019, 19:21:23) [MSC v.1916 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> filename = input()
ex15_sample.txt
>>> txt = open(filename)
>>> txt.read()
'This is stuff I typed into a file.\nIt is really cool stuff.\nLots and lots of fun to have in here.\n'
>>> quit()
PS E:\lpthw>

【学习心得】
1 在python提示符下使用open()打开文件，作者期望怎样实现？
2 python与c的区别：
python脚本中不需要main()函数，直接顺序执行了。不过，到目前为止，脚本中还没有出现任何函数，后面学到函数后，需要再关注下。

原文链接:https://blog.csdn.net/xiaoyuweiwei0605/article/details/104719515