除了操作PYTHONPATH，您还可以创建一个路径配置文件。首先找出Python在哪个目录中搜索这些信息:

python -m site --user-site

出于某种原因，这在Python 2.7中似乎不起作用。你可以使用:

python -c 'import site; site._script()' --user-site

然后在该目录中创建一个.pth文件，其中包含您想要添加的路径(如果目录不存在，则创建该目录)。

例如:

# find directory
SITEDIR=$(python -m site --user-site)

# create if it doesn't exist
mkdir -p "$SITEDIR"

# create new .pth file with our path
echo "$HOME/foo/bar" > "$SITEDIR/somelib.pth"

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.

A <-> B之间的最短路径是一条直线;

import sys
if not 'NEW_PATH' in sys.path:
  sys.path += ['NEW_PATH']

在Mac上:

user@terminal$ env PYTHONPATH=module_path python3
>>> import sys
>>> sys.path
['module_path', 'plus_other_python3_paths',...]

在MacOS上，而不是给出特定库的路径。给出根项目文件夹的完整路径

~/.bash_profile 

让我很开心，例如:

export PYTHONPATH="${PYTHONPATH}:/Users/<myuser>/project_root_folder_path"

这样做之后:

source ~/.bash_profile

在多次撞击墙壁后。最终解决的问题是，在我的CentOS 8中，pip3是旧的，它在安装最新的软件包时显示错误。

现在，我已经下载了Python源包，它是Python-3.10.4，并以通常的方式安装，但是安装后检查在bash中产生了错误。

我不能删除现有的Python，因为这会破坏CentOS的桌面功能。

解决方案:

为构建

./configure //不要添加——prefix=/usr，你需要适当地设置 使-j8 Sudo make install

现在，由于您安装了多个Python，您可以设置别名Python =python3

以及设置PYTHONPATH

export PYTHONPATH="/usr/local/bin/python3.10:/usr/local/lib/python3.10/lib-dynload:/usr/local/lib/python3.10/site-packages"

不要添加PYTHONHOME