Virtualenv
Virtualenv is the virtual environment of python.
It can provide a stand-alone operating environment for a python program or script.
Let’s get started.
Install and Using
Install
Install and Using Virtualenv is very simple.
代码语言：javascript复制> pip install virtualenvJust type in above command in shell, ‘virtualenv’ will be installed immediately.
Tip: For well-known reasons, some python resource packs cannot be downloaded in the country. If you’re experiencing some error stoin, you should to try a scientific way to connect to the Internet.
Activate Command
After the installation is complete. We could just try how to use Virtualenv to create a stand-alone operating environment.
let’s say we’re going to develop a new project that requires a stand-alone Python operating environment, so you can:
代码语言：javascript复制# create a directory
> mkdir testProject
> cd testProject
# create a stand-alone Python running environment
# named testVenv:
> virtualenv --no-site-packages testVenvThe Command ‘virtualenv xxx’ is already could create a stand-alone python operating environment. We add the parameters ‘–no-site-packages’ here for keep sure that don’t copy any third-party packages to this environment.
When the shell says ‘Done’, a stand-alone environment is created.
The way to enter the environment varies depending on the operating system.
Linux or MacOS
In Linux or MacOS, you can enter this stand-alone python operating environment simply by using the “Activate” command.
When you enter the environment, the name of the current environment (testVenv) appears at the beginning of the command line for differentiation.
Windows
In Windows, we typically use ‘cmd’ or ‘powershell’ to operate commands. And their operating command are different.
In cmd mode, we still go to the directory and then execute ‘Activate’.
But in powershell mode, we need to execute a policy change first, and then execute ‘activate.ps1’ script to get into a stand-alone environment.
代码语言：javascript复制Make sure the current powershell window is under administrator privileges. And here’s the modification command.
# change policy
PS> Set-ExecutionPolicy RemoteSigned
# enter in environment
PS> cd D:CodetestProjecttestVenvScripts
PS> .activate.ps1
(testVenv) PS>Some paths in the above sample code have been hidden.
Deactivate
Enter the “deactivate” command directly to shut down the current environment.
Isn’t it very simple? It’s easy to isolate different python environments and avoid them interfering with each other.
In the end
This is my first English technology blog, after which I will try to use English to record all the blogs. I hope it can help me improve my English skill.
