2.2 最快查看包搜索路径的方式
============================

.. image:: http://image.iswbm.com/20200804124133.png

当你使用 import 导入一个包或模块时，Python
会去一些目录下查找，而这些目录是有优先级顺序的，正常人会使用 sys.path
查看。

.. code:: python

   >>> import sys
   >>> from pprint import pprint   
   >>> pprint(sys.path)
   ['',
    '/usr/local/Python3.7/lib/python37.zip',
    '/usr/local/Python3.7/lib/python3.7',
    '/usr/local/Python3.7/lib/python3.7/lib-dynload',
    '/home/wangbm/.local/lib/python3.7/site-packages',
    '/usr/local/Python3.7/lib/python3.7/site-packages']
   >>> 

那有没有更快的方式呢？

我这有一种连 console 模式都不用进入的方法呢？

你可能会想到这种，但这本质上与上面并无区别

.. code:: python

   [wangbm@localhost ~]$ python -c "print('\n'.join(__import__('sys').path))"

   /usr/lib/python2.7/site-packages/pip-18.1-py2.7.egg
   /usr/lib/python2.7/site-packages/redis-3.0.1-py2.7.egg
   /usr/lib64/python27.zip
   /usr/lib64/python2.7
   /usr/lib64/python2.7/plat-linux2
   /usr/lib64/python2.7/lib-tk
   /usr/lib64/python2.7/lib-old
   /usr/lib64/python2.7/lib-dynload
   /home/wangbm/.local/lib/python2.7/site-packages
   /usr/lib64/python2.7/site-packages
   /usr/lib64/python2.7/site-packages/gtk-2.0
   /usr/lib/python2.7/site-packages

这里我要介绍的是比上面两种都方便得多的方法，一行命令即可解决

.. code:: shell

   [wangbm@localhost ~]$ python3 -m site
   sys.path = [
       '/home/wangbm',
       '/usr/local/Python3.7/lib/python37.zip',
       '/usr/local/Python3.7/lib/python3.7',
       '/usr/local/Python3.7/lib/python3.7/lib-dynload',
       '/home/wangbm/.local/lib/python3.7/site-packages',
       '/usr/local/Python3.7/lib/python3.7/site-packages',
   ]
   USER_BASE: '/home/wangbm/.local' (exists)
   USER_SITE: '/home/wangbm/.local/lib/python3.7/site-packages' (exists)
   ENABLE_USER_SITE: True

从输出你可以发现，这个列的路径会比 sys.path
更全，它包含了用户环境的目录。