Getting started with Python

Python is one of the most popular programming languages in the world. Its readable syntax and massive ecosystem of libraries make it the go-to choice for everything from data analysis to machine learning to backend APIs.

Here's what Python is commonly used for:

• •Data science, analysis, and visualization (pandas, matplotlib, Jupyter)
• •Machine learning and AI (TensorFlow, PyTorch, scikit-learn)
• •Automation and scripting (file processing, web scraping, task scheduling)
• •Backend web development (Django, Flask, FastAPI)
• •Scientific computing and research

1. Go to python.org/downloads and click the "Download Python" button.
2. Run the installer.

   ⚠️ Important: Check the box that says "Add python.exe to PATH" before clicking "Install Now".

3. Open a new Command Prompt or PowerShell window when done.

Using Windows? See Pro Tip #1 to set up Git Bash as your default IDE terminal.

pip is Python's package manager — it installs libraries from PyPI (the Python Package Index), a public repository with over 500,000 packages.

Here are the most common pip commands:

pip3 install requests

pip3 uninstall requests

pip3 list

📄 requirements.txt

Instead of installing packages one by one, Python projects use a file called requirements.txt to list all their dependencies. This is similar to how Node.js uses package.json.

A requirements.txt file looks like this:

requests==2.31.0
flask==3.0.0
pandas==2.1.4

To install everything listed in the file:

pip3 install -r requirements.txt

To generate a requirements.txt from your current environment:

pip3 freeze > requirements.txt

A virtual environment is an isolated copy of Python for a specific project. It keeps each project's dependencies separate so they don't interfere with each other — or with your system Python.

Why does this matter? Imagine two projects that need different versions of the same library. Without virtual environments, they would conflict. With virtual environments, each project gets exactly the versions it needs.

Create a virtual environment:

python3 -m venv venv

Activate it:

Windows:

Using Windows? See Pro Tip #1 to set up Git Bash as your default IDE terminal.

venv\Scripts\activate

macOS / Linux:

source venv/bin/activate

You'll see (venv) appear at the beginning of your terminal prompt — this means the virtual environment is active.

To deactivate (return to normal):

deactivate

AI coding agents like Google Antigravity will typically create and activate a virtual environment for you automatically when starting a Python project.

Let's put it all together — create a project folder, set up a virtual environment, install a package, and run a simple Python program.

Create a project folder and navigate into it:

mkdir my-python-project
cd my-python-project

Create and activate a virtual environment:

Windows:

Using Windows? See Pro Tip #1 to set up Git Bash as your default IDE terminal.

python3 -m venv venv
venv\Scripts\activate

macOS / Linux:

python3 -m venv venv
source venv/bin/activate

Install a package — let's use requests, a popular library for making HTTP requests:

pip install requests

Create a file called hello.py with this code:

import requests

response = requests.get("https://uselessfacts.jsph.pl/api/v2/facts/random")
data = response.json()

print("Here's a fun fact:")
print(data["text"])

Run your program:

python3 hello.py

You should see a fun fact printed in your terminal — that data came from a live API on the internet, fetched using the requests library you just installed!

Save your dependencies:

pip freeze > requirements.txt

Now anyone who clones your project can run pip install -r requirements.txt to get the exact same setup.