python修改sys.path不起作用 [英] python modifying sys.path doesn't work

问题描述

我在 /opt/lib/python2.7/site-packages 下有一个新的 numpy 版本，在 /usr/lib/python2.7/下有一个标准(系统)版本dist 包.我想暂时使用新的 numpy 版本，所以我在脚本的开头添加了以下内容:

I have a new numpy version under /opt/lib/python2.7/site-packages, and a standard (system) version under /usr/lib/python2.7/dist-packages. I want to temporarily use the new numpy version so I add the following at the beginning of my script:

In [1]: import sys

In [2]: sys.path.insert(1,'/opt/numpy/lib/python2.7/site-packages')

In [3]: sys.path
Out[3]: 
['',
 '/opt/numpy/lib/python2.7/site-packages',
 '/usr/local/bin',
 '/usr/lib/python2.7/dist-packages',
 '/usr/lib/python2.7',
 '/usr/lib/python2.7/plat-x86_64-linux-gnu',
 '/usr/lib/python2.7/lib-tk',
 '/usr/lib/python2.7/lib-old',
 '/usr/lib/python2.7/lib-dynload',
 '/usr/local/lib/python2.7/dist-packages',
 '/usr/lib/python2.7/dist-packages/PILcompat',
 '/usr/lib/python2.7/dist-packages/gtk-2.0',
 '/usr/lib/pymodules/python2.7',
 '/usr/lib/python2.7/dist-packages/ubuntu-sso-client',
 '/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode',
 '/usr/lib/python2.7/dist-packages/IPython/extensions']

奇怪的是它仍然加载旧的 numpy 版本:

Strangely it still loads the old numpy version:

In [4]: import numpy as np

In [5]: np.__file__
Out[5]: '/usr/lib/python2.7/dist-packages/numpy/__init__.pyc'

有人对此有任何想法吗?

Does anyone has any idea about this?

注1:这个问题是关于python中的sys.path.请不要推荐我使用 virtualenv 或更改 PYTHONPATH.

Note1: This question is about sys.path in python. Please don't recommend me to use virtualenv or change PYTHONPATH.

注2:在我新建的numpy目录下找到以下文件

Note2: the following files are found under my new numpy directory

$ ls /opt/numpy/lib/python2.7/site-packages
easy-install.pth  numpy-1.11.0-py2.7-linux-x86_64.egg  __pycache__  site.py  site.pyc

推荐答案

显然我必须将 numpy .egg 文件添加到 sys.path 中才能使其工作.

Apparently I have to add the numpy .egg file to sys.path in order to make it work.

In [1]: import sys

In [2]: sys.path.insert(1,'/opt/numpy/lib/python2.7/site-packages/numpy-1.11.0-py2.7-linux-x86_64.egg')

In [3]: sys.path
Out[3]: 
['',
 '/opt/numpy/lib/python2.7/site-packages/numpy-1.11.0-py2.7-linux-x86_64.egg',
 '/usr/local/bin',
 '/usr/lib/python2.7/dist-packages',
 '/usr/lib/python2.7',
 '/usr/lib/python2.7/plat-x86_64-linux-gnu',
 '/usr/lib/python2.7/lib-tk',
 '/usr/lib/python2.7/lib-old',
 '/usr/lib/python2.7/lib-dynload',
 '/usr/local/lib/python2.7/dist-packages',
 '/usr/lib/python2.7/dist-packages/PILcompat',
 '/usr/lib/python2.7/dist-packages/gtk-2.0',
 '/usr/lib/pymodules/python2.7',
 '/usr/lib/python2.7/dist-packages/ubuntu-sso-client',
 '/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode',
 '/usr/lib/python2.7/dist-packages/IPython/extensions']

In [4]: import numpy as np

In [5]: np.__file__
Out[5]: '/opt/numpy/lib/python2.7/site-packages/numpy-1.11.0-py2.7-linux-x86_64.egg/numpy/__init__.pyc'

如果我只添加站点包，它不起作用:

It doesn't work if I add the site-packages only:

In [1]: import sys

In [2]: sys.path.insert(1,'/opt/numpy/lib/python2.7/site-packages')

In [3]: sys.path
Out[3]: 
['',
 '/opt/numpy/lib/python2.7/site-packages',
 '/usr/local/bin',
 '/usr/lib/python2.7/dist-packages',
 '/usr/lib/python2.7',
 '/usr/lib/python2.7/plat-x86_64-linux-gnu',
 '/usr/lib/python2.7/lib-tk',
 '/usr/lib/python2.7/lib-old',
 '/usr/lib/python2.7/lib-dynload',
 '/usr/local/lib/python2.7/dist-packages',
 '/usr/lib/python2.7/dist-packages/PILcompat',
 '/usr/lib/python2.7/dist-packages/gtk-2.0',
 '/usr/lib/pymodules/python2.7',
 '/usr/lib/python2.7/dist-packages/ubuntu-sso-client',
 '/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode',
 '/usr/lib/python2.7/dist-packages/IPython/extensions']

In [4]: import numpy as np

In [5]: np.__file__
Out[5]: '/usr/lib/python2.7/dist-packages/numpy/__init__.pyc'

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