python文件IO，练习运用os.path.exists().

最新推荐文章于 2025-11-27 09:27:58 发布

原创最新推荐文章于 2025-11-27 09:27:58 发布 · 1.4w 阅读

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该篇博客介绍如何使用 `os.path.exists()` 判断文件是否存在。通过示例，展示了当文件不存在时如何创建并写入数据，以及如果文件已存在则提示用户。

tgao@tgao-IdeaPad-U430p:~$ ls
Desktop    Downloads         Music     Public          Templates
Documents  examples.desktop  Pictures  pythonPractice  Videos
tgao@tgao-IdeaPad-U430p:~$ cd pythonPractice
tgao@tgao-IdeaPad-U430p:~/pythonPractice$ ls
cookbook_p150.py  cookbook_p29.py   cookbook_p4.py   dw_test_dict.py
cookbook_p22.py   cookbook_p30.py   cookbook_p56.py  helloworld.py
cookbook_p24.py   cookbook_p335.py  cookbook_p8.py   regexdoc.py
cookbook_p27.py   cookbook_p37.py   cookbook_p9.py
tgao@tgao-IdeaPad-U430p:~/pythonPractice$ python3
Python 3.5.2 (default, Nov 23 2017, 16:37:01) 
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.path.exists('cookbook_p150.py')
True
>>> os.path.abspath('cookbook_p150.py')
'/home/tgao/pythonPractice/cookbook_p150.py'
>>> os.path.exists('/home/tgao/pythonPractice/cookbook_p150.py')
True
>>>

问题：判断是否存在某文件，如果存在，则告诉用户。否则写入数据

import os
if not os.path.exists('cookbook_p149.txt'):
	with open('cookbook_p149.txt','w') as f:
		f.write('hello\n')
else:
	print('File already exists')