Installation and use of Python virtual environment under Linux system

When developing Python projects, it is necessary to create multiple Python virtual environments in a virtual environment, because different projects require different resource bundles and related configurations.

Install the virtual environment

Steps:

Open the Linux terminal (shortcut key ctrl+alt+t) and enter the command:

sudo apt install python-virtualenv

sudo easy_install virtualenvwrapper

Note: The above two commands are executed one after the other, after completion of the virtual environment installation.

Or you can use Pip to install, as long as Pip is installed, and Python comes with a pip:

sudo pip install virtualenv

sudo pip install Virtualenvwrapper

Description: The result of the installation is identical, use any one.

Virtualenv is a virtual environment, Virtualenvwrapper Virtualenv is packaged to make it more friendly.

Note: The order of installation cannot be reversed, virtualenvwrapper must depend on virtualenv.

Create a virtual environment

Enter the following command at the terminal:

MKVIRTUALENV Virtual Environment Name

Such as:

Mkvirtualenv mywork

A virtual environment named MyWork is created

The created virtual environment is saved in the/home/.virtualenvs directory and can be viewed in this directory;

The virtual environment is automatically entered when the creation is successful, and the command line prompts to change;

To specify a python version to create a virtual environment

When the above command executes, the system will create the default Python version of the development environment, and generally everyone's computer will install the Python2 and Python3 versions at the same time, sometimes requiring different versions to create a virtual environment.

Mkvirtualenv-p python path Virtual environment name

Cases:

Mkvirtualenv-p/usr/bin/python3 MyWork

-P refers to the shorthand for path

The path of the py installation, which is installed by default in the/usr/bin/directory, and if it is not found at one time, use the command:

Whereis Python3

In the terminal command line search, the desired path appears.

Details: You do not need to go to the/home/.virtualenvs directory, you can execute commands under any directory, and the virtual environment is created in the same location.

Note: Creating a virtual environment is required to be done under networking, otherwise the creation fails.

View and use of virtual environments

Deleting a virtual environment

rmvirtualenv[Virtual Environment Name]

Cases:

Rmvirtualenvmywork

Note: If the current location is in a virtual environment, you need to exit the virtual environment before you can perform the delete

Note: You can perform a delete operation in any directory, and if you do not know the name, you can Rmvirtualen + two times tab to prompt all virtual environments

Exiting a virtual environment

Deactivate

Entering a virtual environment

workon[Virtual Environment Name]

Cases:

Workkonmywork

Note: Pressing workon+ two times the TAB key prompts all virtual environments.

View Python packages installed in a virtual environment

PIP List

Pip Freeze

Two commands can be queried, but the form of display is not the same.

Install Python packages in a virtual environment

Enter the virtual environment, in the terminal input:

The name of the PIP install package

Note: Be sure not to use sudo pip ..., this is to install the Python package in a virtual environment, if you use sudo permissions, the Python package will be installed in the host non-virtual environment, in the virtual environment can not find this package.

Installation and use of Python virtual environment under Linux system