Python – sys.path

測試環境為 CentOS 8 x86_64 (虛擬機)

sys.path 是 python 可搜尋模組的路徑,其儲存資料格式為 list , 其中的 path[0] 為程式所在的路徑.

參考文章 – https://codertw.com/%E7%A8%8B%E5%BC%8F%E8%AA%9E%E8%A8%80/374849/

• 範例 : 使用 PYTHONPATH 環境變數

  [root@localhost ~]# env PYTHONPATH='/root/ben' python3
  Python 3.6.8 (default, Mar 25 2022, 11:15:52) 
  [GCC 8.5.0 20210514 (Red Hat 8.5.0-10)] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import sys
  >>> sys.path
  ['', '/root/ben', '/usr/lib64/python36.zip', '/usr/lib64/python3.6', '/usr/lib64/python3.6/lib-dynload', '/usr/lib64/python3.6/site-packages', '/usr/lib/python3.6/site-packages']
  >>> 
  

• 範例 : 使用 .pth 檔案
  透過建立 .pth 檔案新增可搜尋模組的路徑

  [root@localhost ~]# vi ben.pth
  /rrot/ben
  

  這 .pth 檔案要放在哪裡? 透過 site.getusersitepackages 來檢視.

  >>> import site
  >>> site.getusersitepackages()
  '/root/.local/lib/python3.6/site-packages'
  

  [root@localhost ~]# mkdir -p /root/.local/lib/python3.6/site-packages/
  [root@localhost ~]# cp ben.pth /root/.local/lib/python3.6/site-packages/
  

  重新進入 python 命令列就可以看到新增了 /root/ben 路徑.

  [root@localhost ~]# python3
  Python 3.6.8 (default, Mar 25 2022, 11:15:52) 
  [GCC 8.5.0 20210514 (Red Hat 8.5.0-10)] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import sys
  >>> sys.path
  ['', '/usr/lib64/python36.zip', '/usr/lib64/python3.6', '/usr/lib64/python3.6/lib-dynload', '/root/.local/lib/python3.6/site-packages', '/root/ben', '/usr/lib64/python3.6/site-packages', '/usr/lib/python3.6/site-packages']
  

• 範例 : 透過 sys.path.append

  >>> sys.path.append('/root/ben1')
  >>> sys.path
  ['', '/usr/lib64/python36.zip', '/usr/lib64/python3.6', '/usr/lib64/python3.6/lib-dynload', '/root/.local/lib/python3.6/site-packages', '/root/ben', '/usr/lib64/python3.6/site-packages', '/usr/lib/python3.6/site-packages', '/root/ben1']
  

  不過重新進入需再次使用 sys.path.append 讓路徑新增.

  >>> 
  [8]+  已停止               python3
  [root@localhost ~]# python3
  Python 3.6.8 (default, Mar 25 2022, 11:15:52) 
  [GCC 8.5.0 20210514 (Red Hat 8.5.0-10)] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import sys
  >>> sys.path
  ['', '/usr/lib64/python36.zip', '/usr/lib64/python3.6', '/usr/lib64/python3.6/lib-dynload', '/root/.local/lib/python3.6/site-packages', '/root/ben', '/usr/lib64/python3.6/site-packages', '/usr/lib/python3.6/site-packages']