Python Virtual Environment Explained

What is a Virtual Environment

A virtual environment is simply a tool that separates the dependencies of different projects by creating isolated environments for each project.

It is basically a directory inside your project, so you can create unilimted environments for your project projects. This is one of the most popular tool used by python developers.

Why do we need a Virtual Environment

Imagine you’re working on a project which requires a 3rd-party library and you don’t want to install it globally on your system, it is required for that specific project.

In such cases, virtual environment comes into play. It can create a seperate isolated environment in your project and can store/retrieve packages. Think of it like a virtual space for just your awesome project.

Also, let’s consider another case where you’re working on two projects, project_1 and project_2.

If the project_1 needs python_3.9 and project_2 needs python_3.13, they would be stored in the same directory with same name, so a version conflict may occur. In such cases, virtual environment can be really helpful for you to maintain the dependencies of both the projects.

How to Create a Virtual Environment

To create a virtual environment, you can either use the build-in venv module or the 3rd-party virtualenv module. Here, we can just use the build-in one.

Make sure you’ve pip installed on your system.

Create venv

Open the terminal in your project working directory and paste the following command to create a venv (virtual environment):

python -m venv .venv

Here, I created a virtual environment named .venv, you can name it whatever you desire. This will create a folder called .venv in your current working directory (cwd). This is the folder where all your python packages will run.

Activate venv

After successfully creating a virtual environment, you need to activate it to enter into that isolated environment. Always remember to activate the required virtual environment before working on a project. To activate it, run the following command:

Linux and macOS:

source .venv/bin/activate

Windows:

.venv\Scripts\activate
# or
.venv\Scripts\activate.bat

Once activated, your shell prompt will typically change to include the activated virtual environment, like: (venv) your_username@your_machine:~$. This indicates that the virtual environment is active, and any python packages installed using pip will be instaled within this isolated environment, not globally on your system.

Deactivate venv

To deactivate the virtual environment and return to the system’s global python environment, simply run this command:

deactivate

This command works on all operating systems after activating the virtual environment.

Extras

After doing this couple of times, you might get bored and want something more fun and easy to work with. That’s where package managers like uv, poetry, etc shines. They are not like pip. They have their own virtual env, caching mechanism, lock file generation for faster installation and a build system.

I suggest uv, because it is written in rust, so is faster than other package managers. You can manage projects with commands like:

# create project
uv init <project-name>
# sync lock file and dependencies
uv sync
# add packages
uv add <package-one> <package-two>
# remove packages
uv remove <package-two>
# build and publish
uv build && uv publish

Package managers like this makes your workflow even smoother not a mess. Make sure to check out uv, its cool!