Foundations: Phase 3 — Code as Communication

What This Phase Is

The bridge from understanding to writing. Why code is communication, not just instructions.

Your First Python Program — Hello, World

Write, run, and understand your first program. Why Hello World matters and what it teaches.

Variables — Naming Things

Types, assignment, naming conventions, and why good variable names are a professional skill.

Conditionals — Making Decisions

If/elif/else, boolean logic, comparison operators, and building decision trees in code.

Loops — Doing Things Repeatedly

For loops, while loops, break/continue, nested loops, and avoiding infinite loops.

Functions — Reusable Building Blocks

Defining functions, parameters, return values, scope, and the single responsibility principle.

File I/O — Getting Data In and Out

Reading and writing files, CSV processing, JSON handling, and the with statement.

Reading Code — The Other Half of the Skill

How to read code you didn't write. Tracing execution, identifying patterns, and building comprehension.

Error Handling — When Things Go Wrong in Your Code

Try/except, raising exceptions, error types, and writing defensive code that fails gracefully.

Working With APIs — Talking to Other Programs

HTTP requests from Python, parsing JSON responses, API keys, and building a CLI tool that talks to a real API.

Phase 3 Summary — What You Can Now Do

A recap of every skill built in this phase and what they unlock in Phase 4.