03 - Setting Up Python¶

Home: README

Who this is for¶

Absolute beginners with zero coding experience.
Learners using Windows, macOS, or Linux.
Learners who want exact copy/paste setup steps and expected results.

What you will build¶

A working Python workspace.
A virtual environment (.venv).
A first script and a first passing test.
Safe credential habits for SQL-auth workflows.

Prerequisites¶

One device with internet access.
Permission to install apps on your device.
45 to 90 minutes for first-time setup.
For database labs later in this plan: database credentials (SQLite works locally with no setup; PostgreSQL for production practice).

Step-by-step lab pack¶

Choose your platform¶

Platform	Guide
Windows	Windows Setup
macOS	macOS Setup
Linux	Linux Setup

Each guide walks you through the complete setup: installing Python, choosing an editor, creating a project folder, setting up a virtual environment, running your first script, and running your first test.

Mobile learners (Android/iOS)¶

Mobile devices are fine for early fundamentals but you will need a desktop or laptop for advanced work (drivers, ETL jobs, dashboards, CI).

Android (Termux): Install Termux, then run pkg install -y python and follow the Linux guide — most commands are identical.

iOS: Use a Python app such as Pyto or Pythonista. These apps have built-in editors and consoles. Virtual environments are not fully supported on iOS — treat it as a learning-only path and transition to desktop before enterprise phases.

Expected output¶

A working hello_sme project with:
hello.py
test_hello.py
.venv
python hello.py succeeds.
pytest -q succeeds.
You can explain your credential safety rules.

Break/fix drills¶

Deactivate venv and run pytest to see failure mode.
Rename test_hello.py to hello_test.py and observe discovery behavior.
Intentionally misspell assert and read the traceback.
Switch interpreter in editor, then switch back to the project venv.
Add a fake credential directly in code, then remove it and replace with env var access.

Troubleshooting¶

python or python3 not found: reopen terminal, confirm install finished, reinstall and ensure PATH/shell setup.
See platform-specific troubleshooting in each guide: Windows | macOS | Linux

Mastery check¶

You pass setup when you can: - set up a fresh folder from scratch, - create and activate an isolated environment, - run one script and one test, - explain why credentials must not be hardcoded.