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.

我在Windows Vista中永久添加了Python 3.5

系统>控制面板>系统高级设置>高级(点击)环境变量>系统变量>(如果在变量列中没有看到PYTHONPATH)(点击)新建>变量名称:PYTHONPATH >变量值:

请将目录写在变量值中。这是Blue Peppers回答的细节。

如果有人仍然感到困惑，如果你在Mac上，请执行以下操作:

打开终端 输入open .bash_profile 在弹出的文本文件中，在最后添加这行: 出口到PYTHONPATH = $ PYTHONPATH: foo / bar 保存文件，重新启动终端，就完成了

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.

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。

将export PYTHONPATH="${PYTHONPATH}:/my/other/path"添加到~/。如果PYTHONPATH当前不存在(因为:)，bashrc可能无法工作。

export PYTHONPATH="/my/other/path1"
export PYTHONPATH="${PYTHONPATH}:/my/other/path2"

将以上内容添加到我的~/。bashrc在Ubuntu 16.04上为我完成了这个任务