通过virtualenv可以创建python虚拟环境，而virtualenvwrapper是个管理python虚拟环境的工具，方便创建和切换python虚拟环境

1 安装virtualenvwrapper

pip install virtualenvwrapper

2 配置virtualenvwrapper

追加下面内容到文件~/.bash_profile
WORON_HOME 是存放虚拟环境位置的环境变量，之后创建的 python 虚拟环境都会在 WORON_HOME 所指定的目录中。(~ 这个符号表示当前用户的默认目录，例如，你的Linux用户名是luna，那么 ~ 表示/home/luna，如果你是苹果电脑，那么 ~ 表示/Users/luda。如果你还不确定它表示什么，用命令“cd ~”切换到此目录，然后“pwd”看一下)

export WORKON_HOME=~/PyEnvs
source /usr/local/bin/virtualenvwrapper.sh

使配置生效
source ~/.bash_profile

3 创建Python虚拟环境

创建当前系统默认python版本的虚拟环境并命名为venv
mkvirtualenv venv
创建指定python版本的虚拟环境
mkvirtualenv --python=/usr/bin/python2.7 py27

4 查看已有python虚拟环境

workon

5 切换python虚拟环境

workon py27

6 退出python虚拟环境

deactivate

7 删除python虚拟环境

rm -rf ~/PyEnvs/py27

输出样本

$ mkvirtualenv venv
Using base prefix '/Library/Frameworks/Python.framework/Versions/3.6'
New python executable in /Users/jzongnan/PyEnvs/venv/bin/python3.6
Also creating executable in /Users/jzongnan/PyEnvs/venv/bin/python
Installing setuptools, pip, wheel...
done.
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/venv/bin/predeactivate
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/venv/bin/postdeactivate
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/venv/bin/preactivate
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/venv/bin/postactivate
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/venv/bin/get_env_details
(venv) jzongnan ~

$ mkvirtualenv --python=/usr/bin/python2.7 py27
Running virtualenv with interpreter /usr/bin/python2.7
Already using interpreter /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python
New python executable in /Users/jzongnan/PyEnvs/py27/bin/python
Installing setuptools, pip, wheel...
done.
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/py27/bin/predeactivate
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/py27/bin/postdeactivate
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/py27/bin/preactivate
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/py27/bin/postactivate
virtualenvwrapper.user_scripts creating /Users/jzongnan/PyEnvs/py27/bin/get_env_details
(py27) jzongnan ~

$ workon
py27
venv
(py27) jzongnan ~

$ workon venv
(venv) jzongnan ~

$ deactivate
jzongnan ~

$ rm -rf ~/PyEnvs/py27
jzongnan ~
$ workon
venv