Python3基础 sys.path 查看与修改导包的路径

   Python : 3.7.3

   OS : Ubuntu 18.04.2 LTS

  IDE : pycharm-community-2019.1.3

Conda : 4.7.5

typesetting : Markdown

code

coder@ubuntu:~$ source activate py37
(py37) coder@ubuntu:~$ ipython
Python 3.7.3 (default, Mar 27 2019, 22:11:17) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.5.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import sys                                                              

In [2]: sys.path                                                                
Out[2]: 
['/home/coder/anaconda3/envs/py37/bin',
 '/home/coder/anaconda3/envs/py37/lib/python37.zip',
 '/home/coder/anaconda3/envs/py37/lib/python3.7',
 '/home/coder/anaconda3/envs/py37/lib/python3.7/lib-dynload',
 '',
 '/home/coder/anaconda3/envs/py37/lib/python3.7/site-packages',
 '/home/coder/anaconda3/envs/py37/lib/python3.7/site-packages/IPython/extensions',
 '/home/coder/.ipython']

In [3]: # 导包的时候，按照sys.path列表中的路径进行按顺序进行搜索                                 

In [4]: # 如果在sys.path[0]的路径下找到了，那么就停止搜索，不会去寻找sys.path[1]                 

In [5]: type(sys.path)                                                                           
Out[5]: list

In [6]: sys.path.append("/home/coder")                                                           

In [7]: sys.path                                                                                 
Out[7]: 
['/home/coder/anaconda3/envs/py37/bin',
 '/home/coder/anaconda3/envs/py37/lib/python37.zip',
 '/home/coder/anaconda3/envs/py37/lib/python3.7',
 '/home/coder/anaconda3/envs/py37/lib/python3.7/lib-dynload',
 '',
 '/home/coder/anaconda3/envs/py37/lib/python3.7/site-packages',
 '/home/coder/anaconda3/envs/py37/lib/python3.7/site-packages/IPython/extensions',
 '/home/coder/.ipython',
 '/home/coder']

In [8]: # 这样修改的话，是临时的。再启动时，恢复默认。                                           

In [9]: exit                                                                                     
(py37) coder@ubuntu:~$ ipython
Python 3.7.3 (default, Mar 27 2019, 22:11:17) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.5.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import sys                                                                               

In [2]: sys.path                                                                                 
Out[2]: 
['/home/coder/anaconda3/envs/py37/bin',
 '/home/coder/anaconda3/envs/py37/lib/python37.zip',
 '/home/coder/anaconda3/envs/py37/lib/python3.7',
 '/home/coder/anaconda3/envs/py37/lib/python3.7/lib-dynload',
 '',
 '/home/coder/anaconda3/envs/py37/lib/python3.7/site-packages',
 '/home/coder/anaconda3/envs/py37/lib/python3.7/site-packages/IPython/extensions',
 '/home/coder/.ipython']

In [3]: exit                                                                                     
(py37) coder@ubuntu:~$ conda deactivate
coder@ubuntu:~$

source_code

path = [
    '/home/coder/Downloads/pycharm-community-2019.1.3/helpers',
    '/home/coder/anaconda3/envs/py37/lib/python37.zip',
    '/home/coder/anaconda3/envs/py37/lib/python3.7',
    '/home/coder/anaconda3/envs/py37/lib/python3.7/lib-dynload',
    '/home/coder/anaconda3/envs/py37/lib/python3.7/site-packages',
]

resource

[文档 - English] docs.python.org/3
[文档 - 中文] docs.python.org/zh-cn/3
[规范] www.python.org/dev/peps/pep-0008
[规范] zh-google-styleguide.readthedocs.io/en/latest/google-python-styleguide/python_language_rules
[源码] www.python.org/downloads/source
[ PEP ] www.python.org/dev/peps
[平台] www.cnblogs.com
[平台] gitee.com

Python具有开源、跨平台、解释型、交互式等特性，值得学习。
Python的设计哲学：优雅，明确，简单。提倡用一种方法，最好是只有一种方法来做一件事。
代码的书写要遵守规范，这样有助于沟通和理解。
每种语言都有独特的思想，初学者需要转变思维、踏实践行、坚持积累。