What is Python Virtualenvironment

Python applications will often use packages and modules that don’t come as part of the standard library. Applications will sometimes need a specific version of a library, because the application may require that a particular bug has been fixed or the application may be written using an obsolete version of the library’s interface.

This means it may not be possible for one Python installation to meet the requirements of every application. If application A needs version 1.0 of a particular module but application B needs version 2.0, then the requirements are in conflict and installing either version 1.0 or 2.0 will leave one application unable to run.

The solution for this problem is to create a virtual environment, a self-contained directory tree that contains a Python installation for a particular version of Python, plus a number of additional packages.

Different applications can then use different virtual environments. To resolve the earlier example of conflicting requirements, application A can have its own virtual environment with version 1.0 installed while application B has another virtual environment with version 2.0. If application B requires a library be upgraded to version 3.0, this will not affect application A’s environment.

Installation

This installation was successfully done on Ubuntu 18.04. But it will work most of the Linux Distributions.

Install pip

sudo apt install pip

Install needed Python modules

pip install virtualenv or pip3 install virtualenv virtualenvwrapper

Set a Directory for your Environments

export WORKON_HOME=~/Envs

Add it on your bashprofile

export WORKON_HOME=~/Envs
source /home/bipindas/.local/bin/virtualenvwrapper.sh

Testing the virtualenvironment

bipindas@bipindas-desk:~$ mkvirtualenv web
New python executable in /home/bipindas/Envs/web/bin/python
Installing setuptools, pip, wheel...
done.
virtualenvwrapper.user_scripts creating /home/bipindas/Envs/web/bin/predeactivate
virtualenvwrapper.user_scripts creating /home/bipindas/Envs/web/bin/postdeactivate
virtualenvwrapper.user_scripts creating /home/bipindas/Envs/web/bin/preactivate
virtualenvwrapper.user_scripts creating /home/bipindas/Envs/web/bin/postactivate
virtualenvwrapper.user_scripts creating /home/bipindas/Envs/web/bin/get_env_details
(web) bipindas@bipindas-desk:~$

You can see that, you changed to New environment. Now you can install your own versions

Activate and Deactivate the environment

The following command will Activate your Environment

workon web

The following command will Deactivate your Environment

deactivate

Remove the Virtualenvironment

rmvirtualenv web
Removing web...

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