Python Virtual Environment

This post covers how to set up a Python virtual environment using both pipenv and the built-in venv module.

[01] Why Use a Virtual Environment?

A virtual environment isolates a project’s Python packages from the system-wide Python installation. Without isolation, installing a library for one project can break another project that depends on a different version. Virtual environments solve this by giving each project its own private package directory.

Tool	Key Feature	Best For
venv	Built into Python 3.3+	Simple, dependency-light projects
pipenv	Combines pip + venv + Pipfile.lock	Projects that need reproducible lockfiles

[02] pipenv

pipenv manages both the virtual environment and a Pipfile.lock that pins exact dependency versions, making environments reproducible across machines.

Install pipenv

apt-get install -y python3-pip
pip3 install --user pipenv

Create and Activate the Environment

# Keep the .venv folder inside the project directory
export PIPENV_VENV_IN_PROJECT=true

mkdir myproject
cd myproject

# Create a new virtual environment targeting Python 3.6
python3 -m pipenv --python 3.6

# Install dependencies from Pipfile (or create an empty environment)
python3 -m pipenv install

# Activate the shell
python3 -m pipenv shell

After running pipenv shell, your prompt will change to show the environment name. Run exit to leave it.

Key pipenv Commands

Command	What it does
pipenv install <package>	Install a package and add it to Pipfile
pipenv install --dev <package>	Install a dev-only dependency
pipenv uninstall <package>	Remove a package
pipenv lock	Update Pipfile.lock with pinned versions
pipenv run python script.py	Run a script without activating the shell

[03] venv

venv is built into Python 3 and requires no additional installation. It is the simplest way to create an isolated environment.

Create and Activate

# Create a virtual environment named "venv" in the current directory
python -m venv venv

# Activate on Windows
.\venv\Scripts\activate

# Activate on Linux / macOS
source .venv/bin/activate

Once activated, pip install installs packages into the local environment only. Your prompt will show (venv) to indicate the active environment.

Deactivate

deactivate

Recreate from requirements.txt

# Save current packages
pip freeze > requirements.txt

# On another machine: create a fresh venv and install
python -m venv venv
source venv/bin/activate       # or .\venv\Scripts\activate on Windows
pip install -r requirements.txt

[04] Choosing Between pipenv and venv

• Use venv when you want the smallest footprint and are already managing a requirements.txt.
• Use pipenv when you need a lockfile (Pipfile.lock) for deterministic installs across CI and team members.

Both achieve the same core goal — package isolation — so the right choice depends on your project’s complexity.