Module 5 · Three projects and a shareable repo Lesson 13 of 15
Project 1 — Expense tracker
A menu-driven program that records expenses, saves them to a CSV and prints a monthly total per category. It exercises input, loops, dictionaries and files in one piece of work.
The concept
An expense tracker is a menu-driven program: add an expense, list this month's expenses, show the total per category, quit. It is the smallest project that uses everything in the first four modules at once — input, conditions, loops, functions, dictionaries and file writing — which is why it is project one rather than a bigger, half-finished idea.
A single expenses.csv with the columns date, category, amount is the whole storage layer. No database, no framework, nothing a reviewer has to install to run — a person who can open your project with one command is a person who will actually read it. Read the file into a list of dictionaries at start-up, add to the list as the user works, and write the whole list back when they choose to save.
Common mistakes
The mistake that makes this project fail is building the interface first and the data second. Write the file format down, write one function that parses a line into a dictionary, then build the menu around functions you already know work. It also needs to survive being closed: start it twice, add an expense each time, and check the first one is still there.
Worked example
A single expense.csv with columns date, category, amount is enough — no database, no framework, nothing that can fail to install on a reviewer's machine.
Your practice task
Build it end to end and make sure it survives being closed and reopened without losing the earlier entries.
Do this before moving on. Reading a solution teaches the shape of it; typing it teaches you.
Key takeaway
An expense tracker is a menu-driven program: add an expense, list this month's expenses, show the total per category, quit.
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Finish every lesson to unlock the certificate. Each one ends in a practice task — do them and the final project brief writes itself.