Using Python Virtual Environments

If you're going to be managing multiple python projects on your machine, you should be working within virtual environments. This holds true whether you're working on a local machine or a web server. A virtual environment is essentially a container for your python packages. This containerization allows you to have multiple versions of packages and python itself on the same machine. In this tutorial we'll explore the different packages available to create virtual environments.

1. VENV

Python comes with a built-in package for creating virtual environments called venv which is usually enough for most needs.

To create a virtual environment with venv:

$ python3 -m <env-name>

To activate the environment: On Windows:

> env-name\Scripts\activate.bat

On Linux/MacOs:

$ source env-name/bin/activate

Full list of commands from the python documentation (<venv> represents the environment name)

You can then install packages using the built in package manager pip.

To make working with the venv package easier you can install virtualenvwrapper or virtualenvwrapper-win for Windows.

$ pip install virtualenvwrapper

> pip install virtualenvwrapper-win

To find the location of the virtualenvwrapper.sh on UNIX/LINUX:

$ which virtualenvwrapper.sh

For UNIX/Linux you can then add the following lines to your ~/.bashrc or ~/.profile file

export WORKON_HOME=$HOME/.virtualenvs   
export PROJECT_HOME=$HOME/projects      
source /usr/local/bin/virtualenvwrapper.sh

Then reload the file:

$ source ~/.bashrc

To use use the wrapper on both Windows and UNIX/Linux

Creation:

> mkvirtualenv my-project
(my-project) >

Deactivation:

(my-project) > deactivate
>

Activation:

> workon my-project
(my-project) >

You can browse the documentation for venv, mkvirtualenv and mkvirtualenv-win for more commands.

2. Anaconda

If you have the Anaconda distribution installed then creating a virtual environment is as simple as running the following command:

$ conda create -name <env-name>

To install an environment with a particular version of python:

$ conda create -n myenv python=3.8

To activate your environment:

$ conda activate <env-name>

To deactivate your environment:

$ conda deactivate

To see your available environments:

$ conda env list

You can then install packages using conda install <package>.