From First Function to a Saved List

Your starting point

You have an idea and can ask an assistant to help run a small local project. No prior complete app is required.

• A local project environment you can start with help.
• A willingness to compare actual output with a concrete expected result.

Your finish line

You can explain how input becomes validated data, how small functions produce results, and how a saved record differs from temporary screen state.

Stack up four small wins

1. STEP 1 OF 4

   Trace one input before adding features

   Choose one tiny example such as splitting a bill. Write the input values, the expected result, and one invalid case in plain language. Ask the assistant to identify the relevant code once it exists.

   Bro tip: Write the expected answer beside your input, then point to the code that handles each part. Include one input that should be rejected.

   What you’ll learn

   • Input, decision, output
   • Variable versus displayed label
   • Observable acceptance criteria
   You’re ready to move on when

   You can point to the input, calculation, and displayed output for the same example and say what should happen for the invalid case.

   I can do this step

2. STEP 2 OF 4

   Build and check a calculation

   Complete the Shared Bill Calculator Lab. Verify the worked example before polishing the interface, then check the invalid-input cases.

   Bro tip: Check the 100 bill, 20 percent tip, and four-person example before changing the layout. If it fails, inspect the calculation separately.

   What you’ll learn

   • Functions and return values
   • Numeric validation
   • Separating calculation from display
   You’re ready to move on when

   The bill example produces total 120 and share 30, and invalid input cannot masquerade as a successful result.

   Open project: Shared Bill Calculator Lab

   I can do this step

3. STEP 3 OF 4

   Break a larger rule into functions

   Complete the Text Inspector Practice Lab. Keep a small set of examples that explains its word and line rules.

   Bro tip: Keep a tiny text sample for each counting rule. Change one rule or function at a time so surprising results are easier to explain.

   What you’ll learn

   • Strings, arrays, conditions, and loops
   • Explicit counting rules
   • Repeatable examples
   You’re ready to move on when

   The documented text examples repeat reliably, including empty input and unusual spacing.

   Open project: Text Inspector Practice Lab

   I can do this step

4. STEP 4 OF 4

   Make records survive a fresh launch

   Complete the Local Study Queue Lab. Trace an item from creation through editing, storage, and a fresh launch.

   Bro tip: Create two items with the same title, change just one, and reopen the app. Follow their IDs rather than trusting the displayed names.

   What you’ll learn

   • Stable identity
   • Create, read, update, and delete
   • Persistence and recovery
   You’re ready to move on when

   Two same-title items stay distinct and the saved list reloads with the intended IDs and completion state.

   Open project: Local Study Queue Lab

   I can do this step

Your build lineup

1. Shared Bill Calculator Lab

   Build a small calculator whose inputs, decisions, and results you can explain using real examples.

2. Text Inspector Practice Lab

   Practice breaking one problem into small functions by counting and summarizing text with explicit rules.

3. Local Study Queue Lab

   Combine data structures, state, validation, and persistence in one small study list.

Watch it. Then build it.

Start with a worked example, then connect the recording to your own small, checkable build. Videos open on their creator’s or publisher’s website.

Read Vibe Bro’s written lesson briefing ↗

1. Beginner · Video

   CS50P - Lecture 0 - Functions, Variables

   Harvard CS50 · David J. Malan

   Start programming in Python by following an input through variables, functions, and a returned result.

   For step 2: Build and check a calculation

   Before watching: No prior programming required. Stack: Python; a browser is enough to watch, and a Python environment is needed to practice.

   Watch, then try

   Pause after a small function and predict its output. Use the bill example to distinguish the calculation from what gets printed.

   This is a Python route through the language-neutral project. CS50 provides the lecture, notes, and transcript free; paid certificates are optional.

   Watch video ↗ · Practice: Shared Bill Calculator Lab

   Publisher’s course details · checked October 28, 2026

2. Next step · Video

   CS50P - Lecture 2 - Loops

   Harvard CS50 · David J. Malan

   Practice repeated work with Python loops, lists, and dictionaries before writing larger text-processing rules.

   For step 3: Break a larger rule into functions

   Before watching: Know Python variables, functions, and simple conditions; watch CS50P lectures 0 and 1 first if needed. Stack: Python.

   Watch, then try

   Trace each loop iteration on paper. Then explain how a word list and a frequency dictionary could support the Text Inspector.

   The linked course page also offers short videos on lists, dictionaries, string methods, and slicing. Choose the relevant section before trying the complete exercise.

   Watch video ↗ · Practice: Text Inspector Practice Lab

   Publisher’s course details · checked October 28, 2026

Video links selected October 28, 2026. Selection checks cover publisher metadata and topic fit.

The docs behind it

These references explain the underlying concepts and APIs. The prompt templates and project plans are original examples to adapt to your own setup.

• MDN — functions and returned values
• MDN — browser-local persistence

Documentation links checked October 27, 2026.

Keep the momentum going

• Acceptance criteriaCoding term
• AccessibilityCoding term
• APICoding term