对我来说，当我更改.bash_profile文件时，它起作用了。只是改变.bashrc文件工作，直到我重新启动shell。

对于python 2.7，它应该是这样的:

export PYTHONPATH="$PYTHONPATH:/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python"

在.bash_profile文件的末尾。

为了添加awesomo的答案，你也可以在~/中添加这一行。Bash_profile或~/.profile

对我来说，当我更改.bash_profile文件时，它起作用了。只是改变.bashrc文件工作，直到我重新启动shell。

对于python 2.7，它应该是这样的:

export PYTHONPATH="$PYTHONPATH:/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python"

在.bash_profile文件的末尾。

为了给出更多的解释，Python将使用site.py脚本(通常位于sys. py中)自动构造它的搜索路径(如上所述和这里)。Prefix + lib/python<version>/site-packages以及lib/site-python)。可以获取sys.prefix的值:

python -c 'import sys; print(sys.prefix)'

The site.py script then adds a number of directories, dependent upon the platform, such as /usr/{lib,share}/python<version>/dist-packages, /usr/local/lib/python<version>/dist-packages to the search path and also searches these paths for <package>.pth config files which contain specific additional search paths. For example easy-install maintains its collection of installed packages which are added to a system specific file e.g on Ubuntu it's /usr/local/lib/python2.7/dist-packages/easy-install.pth. On a typical system there are a bunch of these .pth files around which can explain some unexpected paths in sys.path:

python -c 'import sys; print(sys.path)'

因此，可以创建一个.pth文件，并将其放在这些目录中的任何一个目录中(包括上面提到的sitedir)。这似乎是大多数包被添加到系统的方式。而不是使用PYTHONPATH。

Note: On OSX there's a special additional search path added by site.py for 'framework builds' (but seems to work for normal command line use of python): /Library/Python/<version>/site-packages (e.g. for Python2.7: /Library/Python/2.7/site-packages/) which is where 3rd party packages are supposed to be installed (see the README in that dir). So one can add a path configuration file in there containing additional search paths e.g. create a file called /Library/Python/2.7/site-packages/pip-usr-local.pth which contains /usr/local/lib/python2.7/site-packages/ and then the system python will add that search path.

这适用于Windows

在Windows上，使用Python 2.7进入Python安装文件夹。 开放的Lib /网站。 将example.pth空文件添加到此文件夹。 将所需的路径添加到文件中，每行一个。

然后，您将能够从脚本中看到这些路径中的所有模块。

受到andrei-deusteanu答案的启发，以下是我的版本。这允许您在site-packages目录中创建许多额外的路径。

import os

# Add paths here.  Then Run this block of code once and restart kernel. Paths should now be set.
paths_of_directories_to_add = [r'C:\GIT\project1', r'C:\GIT\project2', r'C:\GIT\project3']

# Find your site-packages directory
pathSitePckgs = os.path.join(os.path.dirname(os.__file__), 'site-packages')

# Write a .pth file in your site-packages directory
pthFile = os.path.join(pathSitePckgs,'current_machine_paths.pth')
with open(pthFile,'w') as pth_file:
    pth_file.write('\n'.join(paths_of_directories_to_add))

print(pthFile)