Python virtual environment can provide an independent interpretation environment, dependency packages and other resources for a Python project, which can not only isolate the conflicts caused by different Python versions of different projects, but also facilitate project release.
virtualenv
Virtualenv can be used to create a separate Python environment, which will create an executable file containing the required files for the project.
Install virtualenv
$ pip install virtualenv
Copy the code
Configure the source address for PIP to install third-party libraries
As we all know, the domestic connection to the foreign server will be relatively slow, sometimes set download often timeout. At this time you can try to use the domestic excellent douban source image to install.
Install VirtualEnv using Douban source
pip install -i https://pypi.douban.com/simple virtualenv
Copy the code
Virtualenv usage method
The following command creates a directory (virtual environment) under the current directory called env, which contains a separate Python runtime and a copy of PIP to install the other packge
virtualenv env
Copy the code
Of course you can choose the Python interpreter when creating env, for example:
virtualenv -p /usr/local/bin/python3 venv
Copy the code
By default, virtual environments rely on site packages in the system environment. That is, third-party packages already installed in the system are also installed in the virtual environment. If you do not want to rely on these packages, you can add the parameter –no-site-packages to the virtual environment
Virtualenv --no-site-packagesCopy the code
Start the Virtual Environment
cd ENV
source ./bin/activate
Copy the code
Note that the command line will have an additional (ENV), which is the name of the virtual environment, and all modules will be installed into this virtual environment only.
Exiting a Virtual Environment
deactivate
Copy the code
To delete the virtual environment, simply run the rm -rf venv/ command.
Install Python Packages in the virtual environment
Virtualenv comes with the PIP installation tool, so the packages you need to install can be run directly:
PIP InstallCopy the code
Virtualenvwrapper
Virtualenvwrapper is a virtual environment management tool that manages the location of the created virtual environment and makes it easy to view the name of the virtual environment and switch to the specified virtual environment.
Install (make sure virtualEnv is installed)
pip install virtualenvwrapper
Copy the code
Or use douban source
pip install -i https://pypi.douban.com/simple virtualenvwrapper-win
Copy the code
Note:
The installation must be performed in a non-virtual environment
Creating a VM
mkvirtualenv env
Copy the code
After the virtual environment is created, the system automatically switches to the created virtual environment
You can also specify the Python version of the virtual machine
mkvirtualenv env -p C:\python27\python.exe
Copy the code
List the virtual environments
Workon or lsvirtualenvCopy the code
Start/switch the virtual environment
Run the workon [virtual-name] command to switch to the corresponding virtual environment
Workon [Virtual environment name]Copy the code
Deleting a Virtual Environment
Rmvirtualenv [Virtual environment name]Copy the code
To leave the virtual environment, use the same command as virutalenv
deactivate
Copy the code