【python】（虚拟环境）安装，配置和使用
【python】（虚拟环境）安装，配置和使用
写在前面的话
本文为个人在 OneNote 上的笔记，分享到网络上（我的 CSDN blog 上）。仅供参考。
并非手把手一步步的教程。所以有看得不明白的地方欢迎在评论区解释和补充，但是请勿喷一篇个人笔记。
一行一行输入命令即可
Reference
Pipenv & 虚拟环境 @ readthedocs.io
https://blog.csdn.net/xx790008409/article/details/78461929
开始操作
$ sudo pip3 install virtualenv
Collecting virtualenv
Downloading https://files.pythonhosted.org/packages/b6/30/96a02b2287098b23b875bc8c2f58071c35d2efe84f747b64d523721dc2b5/virtualenv-16.0.0-py2.py3-none-any.whl (1.9MB)
100% |████████████████████████████████| 1.9MB 12.4MB/s
Installing collected packages: virtualenv
Successfully installed virtualenv-16.0.0
$ mkdir usePythonVirtualEvn
$ cd use…
$ virtualenv usePythonVirtualEvn
Using base prefix '/usr'
New python executable in /home//usePythonVirtualEvn/usePythonVirtualEvn/bin/python3
Also creating executable in /home//usePythonVirtualEvn/usePythonVirtualEvn/bin/python
Installing setuptools, pip, wheel...done.
$ ### 以上为方法一 ?
$ ### 不论是上述方法一还是下面要通过使用 virtualenvwrapper 管理虚拟环境； virtualenv 都是要 install 的。
$ sudo pip3 install virtualenvwrapper
Collecting virtualenvwrapper
Collecting stevedore (from virtualenvwrapper)
Requirement already satisfied: virtualenv in /usr/local/lib/python3.5/dist-packages (from virtualenvwrapper) (16.0.0)
Collecting virtualenv-clone (from virtualenvwrapper)
Requirement already satisfied: six>=1.10.0 in /usr/lib/python3/dist-packages (from stevedore->virtualenvwrapper) (1.10.0)
Collecting pbr!=2.1.0,>=2.0.0 (from stevedore->virtualenvwrapper)
Downloading https://files.pythonhosted.org/packages/69/1c/98cba002ed975a91a0294863d9c774cc0ebe38e05bbb65e83314550b1677/pbr-4.2.0-py2.py3-none-any.whl (100kB)
100% |████████████████████████████████| 102kB 1.7MB/s
Installing collected packages: pbr, stevedore, virtualenv-clone, virtualenvwrapper
Successfully installed pbr-4.2.0 stevedore-1.29.0 virtualenv-clone-0.3.0 virtualenvwrapper-4.8.2
$ mkdir Devl ## `pwd` => /home//Devl
$ vim ~/.bashrc
add:
export WORKON_HOME=$HOME/.virtualens
export PROJECT_HOME=$HOME/Devl # 注：个人还不明 该文件夹对于 virtualenv 的作用
source /usr/local/bin/virtualenvwrapper.sh
$ source ~/.bashrc
/usr/bin/python: No module named virtualenvwrapper
virtualenvwrapper.sh: There was a problem running the initialization hooks.
If Python could not import the module virtualenvwrapper.hook_loader,
check that virtualenvwrapper has been installed for
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python and that PATH is
set properly.
$ /usr/bin/python -V
Python 2.7.13+
$ ## 将 /usr/bin/python 删除，重新 链接为 python3
$ #### 更新注释，解决该问题两种方法，一是按上文红字指定 VIRTUALENVWRAPPER_PYTHON 到
$ #### 之前安装该 virtualenv（已经 virtualenvwrapper）使用的 pip 版本（上面用的 pip3 对应 python3.X）
$ #### 方法二即修改 python 软连接 使 $ python -V => Python 3.X.X；
$ #### 但是建议直接链接到 $ ln -s /usr/bin/python3.5 $HOME/bin/python
$ #### 然后再 vim $HOME/.bashrc 新增一行： export PATH=$HOME/bin:$PATH ## 该行放在其它新增行前面。
$ #### 当然，直接在 /usr/bin/ 下修改 python 这个软连接的版本也是可以的 ?
$ cd /usr/bin/ && sudo rm python && sudo ln -s python3 python && cd -
$ /usr/bin/python -V
Python 3.5.4rc1
$ source ~/.bashrc ## 第一次执行才会输出这么多信息
virtualenvwrapper.user_scripts creating /home//.virtualens/premkproject
virtualenvwrapper.user_scripts creating /home//.virtualens/postmkproject
virtualenvwrapper.user_scripts creating /home//.virtualens/initialize
virtualenvwrapper.user_scripts creating /home//.virtualens/premkvirtualenv
virtualenvwrapper.user_scripts creating /home//.virtualens/postmkvirtualenv
virtualenvwrapper.user_scripts creating /home//.virtualens/prermvirtualenv
virtualenvwrapper.user_scripts creating /home//.virtualens/postrmvirtualenv
virtualenvwrapper.user_scripts creating /home//.virtualens/predeactivate
virtualenvwrapper.user_scripts creating /home//.virtualens/postdeactivate
virtualenvwrapper.user_scripts creating /home//.virtualens/preactivate
virtualenvwrapper.user_scripts creating /home//.virtualens/postactivate
virtualenvwrapper.user_scripts creating /home//.virtualens/get_env_details
$ cd useWorkon
$ mkvirtualenv useWorkon
Using base prefix '/usr'
New python executable in /home//.virtualens/useWorkon/bin/python3
Also creating executable in /home//.virtualens/useWorkon/bin/python
Installing setuptools, pip, wheel...done.
virtualenvwrapper.user_scripts creating /home//.virtualens/useWorkon/bin/predeactivate
virtualenvwrapper.user_scripts creating /home//.virtualens/useWorkon/bin/postdeactivate
virtualenvwrapper.user_scripts creating /home//.virtualens/useWorkon/bin/preactivate
virtualenvwrapper.user_scripts creating /home//.virtualens/useWorkon/bin/postactivate
virtualenvwrapper.user_scripts creating /home//.virtualens/useWorkon/bin/get_env_details
(useWorkon) @-HP-pro-3330:useWorkon$
(useWorkon) @-HP-pro-3330:useWorkon$
(useWorkon) @-HP-pro-3330:useWorkon$ workon
useWorkon
(useWorkon) @-HP-pro-3330:useWorkon$ ## workon --help
---exit----
---Enter virtual env by workon: ---
@-HP-pro-3330:useWorkon$ workon
useWorkon
@-HP-pro-3330:useWorkon$
@-HP-pro-3330:useWorkon$ workon useWorkon
(useWorkon) @-HP-pro-3330:useWorkon$
(useWorkon) @-HP-pro-3330:useWorkon$ deactive
为了在 Windows 上使用 虚拟环境，花一些时间
MSYS => 即 MinGW
安装在 C:\MinGW 下，
MSYS 窗口： C:\MinGW\msys\1.0\msys.bat
运行 msys.bat 就是 MinGW.exe (cmd)
MSYS 很烂！ 尝试使用 cygwin！
cygwin 的 python 是 python34 没有找到 opencv-python
user > md .virtualenvs
直接使用 CMD！
user > pip install --user virtualenv
user > pip install --user virtualenvwrapper
使用 ** 创建了一个 WORKON_HOME 环境变量：
virtualenv 和 virtualenvwrapper 一样安装，没有不同。
> mkvirtualenv scrstROI
Using base prefix 'd:\\software\\softwaredevelop\\python35'
New python executable in C:\Users\joseph\.virtualenvs\scrstROI\Scripts\python3.exe
Also creating executable in C:\Users\joseph\.virtualenvs\scrstROI\Scripts\python.exe
Installing setuptools, pip, wheel...done.
(scrstROI) C:\Users\joseph>## 看起来也是完全可以正常使用的。
我摘录的 virtualenvwrapper 的官网参考
pip install --user XXX -i https://pypi.tuna.tsinghua.edu.cn/simple/
https://virtualenvwrapper.readthedocs.io/en/latest/install.html
安装 “workon”
这个链接对 workon 的虚拟环境和工作原理可以有一定的理解
https://virtualenvwrapper.readthedocs.io/en/latest/command_ref.html
并且它提供了相关的 command
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