A Quick Guide for Creating Python Virtual Environments

Many a time, you might have come across situations where your existing Python interpreter gets loaded & messed up with too many unrelated libraries leading to cumbersome.

To avoid such situations, the Python community always suggests having a separate Virtual Environment for each task/project.

Ways of Creating a Virtual Environment:

1. Virtualenv

2. Pipenv (My favorite)

1. Prerequisites

Install pip

Usually, Python3 comes with pip preinstalled. If you get an error “pip command not found”, use the following command to install pip:

sudo easy_install pip

2. Virtualenv

A tool for creating isolated virtual Python environments.

Install virtualenv

Virtualenv is a tool to create isolated Python projects. You can think of it as a cleanroom, isolated from other versions of Python and libraries.

Enter this command into the terminal:

sudo pip install virtualenv

Start virtualenv

Navigate to where you want to store your code, e.g., navigate to your project folder for which you want to create a separate virtual environment.

Create a new directory

mkdir my_project && cd my_project

Now, inside my_project folder, create a new virtualenv

virtualenv venv

here ‘venv’ is the name of the virtual environment getting created

Activate virtualenv

source venv/bin/activate

Deactivate virtualenv

deactivate

Python Version on the Virtual Environment

python --version

Install Packages

• Create a ‘requirements.txt’ file
• Add the name of the Python packages you need to install in the virtual env (each package in separate lines)
• Run the below command

pip install -r requirements.txt

Check installed packages

pip list

3. Pipenv

Pipenv is a Python virtual environment management tool. This is a tool that combines virtual environments with package management. It creates a new virtual environment for each project and automatically installs the required packages from a Pipfile. It’s designed to simplify the process of managing dependencies for your projects and provides a simpler interface than virtualenv.

pip install pipenv

Once you’ve done that, you can effectively forget about pip since Pipenv essentially acts as a replacement.

virtualenv -p python3 .venvpipenv install

If .venv folder is not created/not found, then pipenv creates a virtual environment in the default location on your system. Now, two new files, the [Pipfile](https://github.com/pypa/pipfile) (which is meant to replace requirements.txt) and the Pipfile.lock (which enables deterministic builds) will get created.

pipenv shell

This will create a virtual environment using the .venv folder in your project folder.

pipenv check

This will scan your dependency graph for known security vulnerabilities!

pipenv lock -r

This will convert Pipfileand Pipfile.lock into a requirements.txt file very easily.

In this tutorial, we learned how Python virtual environments avoid conflicts between dependencies of different projects or system-wide. Also, we learned how to work on distinct projects with different dependencies by switching between these self-contained environments using the two simple but powerful methods.

Happy to share my personal experiences!

Resources

• https://towardsdatascience.com/manage-your-python-virtual-environment-with-conda-a0d2934d5195
• https://docs.pipenv.org/advanced/#configuration-with-environment-variables