Python3虚拟环境--venv

Python3.3以上的版本通过venv模块原生支持虚拟环境，可以代替之前的virtualenv。

该venv模块提供了创建轻量级“虚拟环境”，提供与系统Python的隔离支持。每一个虚拟环境都有其自己的Python二进制（允许有不同的Python版本创作环境），并且可以拥有自己独立的一套Python包。

注意：python3.3中使用”venv”命令创建的环境不包含”pip”，需进行手动安装。Python3.4中改进了这一缺陷。

创建虚拟环境

 python -m venv myvenv

此命令会在当前目录下生成一个名为myvenv的目录，myenv也是创建的虚拟环境名。

激活环境：

/Scripts/activate.bat

退出环境：

/Scripts/deactivate.bat

附：

venv使用参数：

 usage: venv [-h] [--system-site-packages] [--symlinks] [--clear]
             [--upgrade] [--without-pip] ENV_DIR [ENV_DIR ...]

 Creates virtual Python environments in one or more target directories.

 positional arguments:
   ENV_DIR             A directory to create the environment in.

 optional arguments:
   -h, --help             show this help message and exit
   --system-site-packages Give access to the global site-packages dir to the
                          virtual environment.
   --symlinks             Try to use symlinks rather than copies, when symlinks
                          are not the default for the platform.
   --copies               Try to use copies rather than symlinks, even when
                          symlinks are the default for the platform.
   --clear                Delete the environment directory if it already exists.
                          If not specified and the directory exists, an error is
                          raised.
   --upgrade              Upgrade the environment directory to use this version
                          of Python, assuming Python has been upgraded in-place.
   --without-pip          Skips installing or upgrading pip in the virtual
                          environment (pip is bootstrapped by default)