如何为单个版本修改PYTHONPATH？

Question

我想把这个文件夹添加到我的python2.7的路径里。

/usr/local/lib/python2.7/site-packages

我可以这样做：

sys.path.append('/usr/local/lib/python2.7/site-packages')

或者我也可以把这一行加到我的 ~/.profile 或 ~/.bashrc 文件里。

export PYTHONPATH=/usr/local/lib/python2.7/site-packages:$PYTHONPATH

不过，这样做会把同一个文件夹也添加到我的python2.6的路径里。

import sys
from pprint import pprint as pp
pp(sys.path)
['',
 '/usr/local/lib/python2.7/site-packages',
 '/Users/Leo/Desktop/ReactiveFlows/Homework/HW1/HW1/Cantera',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python26.zip',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-darwin',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac/lib-scriptpackages',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-tk',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-old',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-dynload',
 '/Library/Python/2.6/site-packages',
 '/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/PyObjC']

Answer 1

有很多方法可以做到这一点，具体可以参考 修改Python的搜索路径。

其中一种方法是，在 /Library/Python/2.7/site-packages 目录下添加一个 local.pth 文件（或者在Python2.7的 sys.path 中已经列出的任何目录），这个文件里包含以下内容：

/usr/local/lib/python2.7/site-packages