Environment

Virtual Environments

Virtual environments (venv) isolate your project’s dependencies from the system Python so different projects don’t conflict.

Create and activate a venv:

# Create a venv in the .venv folder (convention)
python -m venv .venv

# On Windows Command Prompt
.venv\Scripts\Activate.bat

# On Windows PowerShell
.venv\Scripts\Activate.ps1

# Activate (macOS/Linux)
source .venv/bin/activate

# Verify
python -V

Deactivate with deactivate.

# Activate (macOS/Linux)
source .venv/bin/deactivate

# On Windows PowerShell
# .venv\Scripts\Deactivate.ps1

Installing Packages (pip)

• PyPI - The Python Package Index

Install, upgrade, uninstall:

pip install numpy
pip install --upgrade pip
pip uninstall numpy

Freeze your current environment to a requirements file:

pip freeze > requirements.txt

Install from a requirements.txt:

pip install -r requirements.txt

Running Modules

Use the -m flag to run installed modules and ensure the correct interpreter is used:

python -m http.server 8000

Common Workflows

# 1) Create project and venv
mkdir myapp && cd myapp
python -m venv .venv
source .venv/bin/activate

# 2) Install deps
pip install numpy

# 3) Save exact versions
pip freeze > requirements.txt

# 4) Recreate env later
venv .venv
source .venv/bin/activate
pip install -r requirements.txt

Jupyter Notebook + VS Code

Note

• Make sure you have VS Code installed
• and created a Python virtual environment (venv)

Extensions

• https://marketplace.visualstudio.com/items?itemName=ms-python.python
• https://marketplace.visualstudio.com/items?itemName=ms-toolsai.jupyter

Optional Extensions

• https://marketplace.visualstudio.com/items?itemName=Google.colab

JupyterLab

JupyterLab is the next-generation web interface for Jupyter notebooks, consoles, and file management.

Install

pip install jupyterlab

Run

# Start JupyterLab (opens in your browser)
jupyter lab

• If the browser does not open, copy the token URL printed in the terminal to your browser.

Stop

• Stop the server with Ctrl+C in the terminal.

Google Colab

• Google Colab

Free, cloud-based platform that allows users to write and execute Python code in a Jupyter Notebook environment.