python-centos7下安装python3虚拟环境

1.创建python的虚拟环境

[root@python ~]# mkdir -p /virtualenvs

安装虚拟环境virtualenv

[root@python ~]#   pip3 install virtualenv -i https://pypi.tuna.tsinghua.edu.cn/simple/

安装虚拟环境扩展包

[root@python   virtualenvs]# pip3 install virtualenvwrapper    -i https://pypi.tuna.tsinghua.edu.cn/simple/

2. 修改用户家目录下的配置文件.bashrc，添加如下内容

修改配置文件

#查找一下安装的虚拟环境扩展包文件
[root@python virtualenvs]# find / -name virtualenvwrapper.sh
/usr/local/python3/bin/virtualenvwrapper.sh

#配置环境变量
[root@python virtualenvs]# vim /etc/profile
[root@python virtualenvs]# tail -n 4 /etc/profile
export WORKON_HOME=/virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 
source /usr/local/python3/bin/virtualenvwrapper.sh

执行环境文件，重新加载文件，使配置配置文件生效

[root@python virtualenvs]# source /etc/profile
virtualenvwrapper.user_scripts creating /virtualenvs/premkproject
virtualenvwrapper.user_scripts creating /virtualenvs/postmkproject
virtualenvwrapper.user_scripts creating /virtualenvs/initialize
virtualenvwrapper.user_scripts creating /virtualenvs/premkvirtualenv
virtualenvwrapper.user_scripts creating /virtualenvs/postmkvirtualenv
virtualenvwrapper.user_scripts creating /virtualenvs/prermvirtualenv
virtualenvwrapper.user_scripts creating /virtualenvs/postrmvirtualenv
virtualenvwrapper.user_scripts creating /virtualenvs/predeactivate
virtualenvwrapper.user_scripts creating /virtualenvs/postdeactivate
virtualenvwrapper.user_scripts creating /virtualenvs/preactivate
virtualenvwrapper.user_scripts creating /virtualenvs/postactivate
virtualenvwrapper.user_scripts creating /virtualenvs/get_env_details

3. 创建python3虚拟环境的命令如下

创建虚拟环境，mkvirtualenv “虚拟环境名称”
- 创建命令：
```
mkvirtualenv 环境名称   
```

执行创建虚拟环境命令

[root@python virtualenvs]# mkvirtualenv  python_3.8_base
which: no virtualenv in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin)
ERROR: virtualenvwrapper could not find virtualenv in your path

#提示报错
我们需要链接一下virtualenv
[root@python virtualenvs]# ln -s /usr/local/python3/bin/virtualenv /usr/bin/virtualenv

重新执行创建虚拟环境命令

root@python virtualenvs]# mkvirtualenv  python_3.8_base
created virtual environment CPython3.7.4.final.0-64 in 969ms
  creator CPython3Posix(dest=/virtualenvs/python_3.8_base, clear=False, global=False)
  seeder FromAppData(download=False, pip=bundle, setuptools=bundle, wheel=bundle, via=copy, app_data_dir=/root/.local/share/virtualenv)
    added seed packages: pip==20.1.1, setuptools==49.2.0, wheel==0.34.2
  activators BashActivator,CShellActivator,FishActivator,PowerShellActivator,PythonActivator,XonshActivator
virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/predeactivate
virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/postdeactivate
virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/preactivate
virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/postactivate
virtualenvwrapper.user_scripts creating /virtualenvs/python_3.8_base/bin/get_env_details

切换虚拟环境：使用"workon 虚拟环境名称" 切换虚拟环境

命令示例：

(Flask_cmdb)   [root@python virtualenvs]# workon python_3.8_base   
(python_3.8_base)  [root@python virtualenvs]#

退出虚拟环境：使用 “deactivate”命令退出虚拟环境
- 命令示例
```
(python_3.8_base)   [root@python virtualenvs]# deactivate   
```

删除虚拟环境：使用“rmvirtualenv 虚拟环境名称”

命令示例：

[root@python   virtualenvs]# rmvirtualenv python_3.8_base   Removing   python_3.8_base...

改为阿里云的pip库

[root@python virtualenvs]# mkdir -p ~/.pip
[root@python virtualenvs]# vim ~/.pip/pip.conf
[root@python virtualenvs]# cat ~/.pip/pip.conf 
[global]
index-url = http://mirrors.aliyun.com/pypi/simple/

[install]
trusted-host=mirrors.aliyun.com