Learn Python • #12 Final Project • Build an Expense Tracking App!

Introduction

In this tutorial, we will guide you through creating a personal expense tracking app using Python. This final project will help you utilize the skills you've learned throughout the course by getting user input, storing data in a spreadsheet, and categorizing expenses. By following these steps, you will not only build a functional app but also gain experience in project planning and implementation.

Step 1: Define Project Specifications

Before diving into coding, outline the main features of your expense tracker app. Consider the following specifications:

• Ability to input expense data through the terminal.
• Save expenses in a structured format (e.g., CSV file).
• Categorize expenses (e.g., food, transport, entertainment).
• Summarize total expenses.
• Track remaining budget.

Step 2: Create an Expense Class

Start by defining an "Expense" class to encapsulate the properties of an expense. This class will include:

• Attributes for the amount, category, and description of the expense.
• A method to display expense details.

Here’s a basic example of what your class might look like:

class Expense:
    def __init__(self, amount, category, description):
        self.amount = amount
        self.category = category
        self.description = description

    def display(self):
        return f"{self.amount} - {self.category}: {self.description}"

Step 3: Set Up the Main Project Structure

Organize your project by creating the following files:

• main.py: The main script to run your application.
• expenses.csv: A file to store the expense data.
• expense.py: The file containing the "Expense" class.

This structure will help manage your code efficiently.

Step 4: Get User Expenses

Implement a function in main.py to collect user input for expenses. Ensure it prompts the user for:

• Expense amount
• Expense category
• Description of the expense

You can use the input() function for this purpose:

def get_expense_input():
    amount = float(input("Enter the expense amount: "))
    category = input("Enter the expense category: ")
    description = input("Enter a brief description: ")
    return Expense(amount, category, description)

Step 5: Save Expenses to a File

To persist the data, write a function to save expenses to a CSV file. Open the file in append mode and write the expense details:

import csv

def save_expense(expense):
    with open('expenses.csv', mode='a', newline='') as file:
        writer = csv.writer(file)
        writer.writerow([expense.amount, expense.category, expense.description])

Step 6: Summarize All Expenses

Create a function to read the CSV file and summarize total expenses. This function should:

• Read all entries.
• Calculate the total amount spent.

Example implementation:

def summarize_expenses():
    total = 0
    with open('expenses.csv', mode='r') as file:
        reader = csv.reader(file)
        for row in reader:
            total += float(row[0])
    return total

Step 7: Group Expenses by Category

To analyze spending habits, implement a method to group expenses by category. Create a dictionary to hold category totals:

def group_expenses_by_category():
    category_totals = {}
    with open('expenses.csv', mode='r') as file:
        reader = csv.reader(file)
        for row in reader:
            category = row[1]
            amount = float(row[0])
            if category in category_totals:
                category_totals[category] += amount
            else:
                category_totals[category] = amount
    return category_totals

Step 8: Track Remaining Budget

Allow users to set a budget and track how much they have left after each expense. Implement a function that checks the remaining budget:

def track_budget(budget):
    total_expenses = summarize_expenses()
    return budget - total_expenses

Conclusion

In this tutorial, you've built a simple yet effective expense tracking app using Python. You learned how to structure your project, create classes, manage user input, and store data in files. With this foundation, you can expand the app by adding features such as data visualization or user authentication. Continue exploring Python and consider enhancing your app for real-world applications!