Personal Expense Tracker with File Handling

1) Project Overview

The Personal Expense Tracker helps users record, view, and manage their daily expenses.

It allows the user to add, view, and analyze expenses saved in a local text file.

This project simulates how real-world expense tracking or budgeting apps (like Wallet or Mint) store and organize data — using simple file handling operations in Python.

💡 Why it's useful: This tool helps users monitor their spending patterns and keep their financial records organized — a valuable skill for personal finance management and data handling practice.

2) Learning Objectives

By completing this project, learners will:

🧾 Learn file handling operations: reading, writing, and appending data
📂 Understand how to store structured data in text or CSV format
🧮 Use functions to modularize and organize code
🕹️ Practice building a menu-driven console application
🔁 Apply loops, conditionals, and exception handling in a real scenario

3) Step-by-Step Explanation

Follow these steps to build the expense tracker:

Set Up the Project – Create a Python file named expense_tracker.py
Design Menu Options – The program should offer options: 1.Add new expense, 2.View all expenses, 3.View total expenses, 4.Exit
Define File Structure – Each expense will be saved in a text file (expenses.txt) in the following format: Date | Category | Amount | Description
Implement Core Functions – You'll need:
- add_expense() → Adds a new record and saves it to file
- view_expenses() → Displays all saved records
- view_total_expense() → Calculates total from the file
Use File Handling – Use with open('expenses.txt', 'a') for adding data and with open('expenses.txt', 'r') for reading data
Add Validation – Validate user input to ensure the amount is numeric
Run Inside a Loop – Keep showing the menu until the user chooses to exit

4) Complete, Well-Commented, and Verified Python Code

You can copy this into a file named expense_tracker.py and run it.

Try it Yourself »

# ----------------------------------------------------
# 💰 Personal Expense Tracker using File Handling
# ----------------------------------------------------
# Author: Your Name
# Level: Intermediate
# Verified: Python 3.8+
# ----------------------------------------------------

import os
from datetime import datetime

# File name for storing expenses
FILE_NAME = "expenses.txt"

def add_expense():
    """Add a new expense entry."""
    print("\n--- Add New Expense ---")
    
    date = datetime.now().strftime("%Y-%m-%d")  # auto-fill today's date
    category = input("Enter category (Food, Transport, etc.): ").title()
    
    # Validate numeric input
    while True:
        try:
            amount = float(input("Enter amount (in USD): "))
            break
        except ValueError:
            print("❌ Invalid amount. Please enter a number.")
    
    description = input("Enter short description: ")
    
    # Save to file
    with open(FILE_NAME, "a") as file:
        file.write(f"{date} | {category} | {amount:.2f} | {description}\n")
    
    print("✅ Expense added successfully!")


def view_expenses():
    """Display all recorded expenses."""
    print("\n--- View All Expenses ---")
    
    if not os.path.exists(FILE_NAME):
        print("No expenses recorded yet!")
        return
    
    with open(FILE_NAME, "r") as file:
        lines = file.readlines()
    
    if not lines:
        print("No expenses to display.")
        return
    
    print(f"{'Date':<12} | {'Category':<12} | {'Amount($)':<10} | Description")
    print("-" * 55)
    
    for line in lines:
        print(line.strip())


def view_total_expense():
    """Calculate and display total spent amount."""
    print("\n--- Total Expenses ---")
    
    if not os.path.exists(FILE_NAME):
        print("No expenses found!")
        return
    
    total = 0.0
    with open(FILE_NAME, "r") as file:
        for line in file:
            parts = line.strip().split("|")
            if len(parts) >= 3:
                try:
                    total += float(parts[2])
                except ValueError:
                    continue
    
    print(f"💵 Total Spent: ${total:.2f}")


def main():
    """Main function to run the menu-based expense tracker."""
    while True:
        print("\n========== Personal Expense Tracker ==========")
        print("1️⃣  Add New Expense")
        print("2️⃣  View All Expenses")
        print("3️⃣  View Total Expenses")
        print("4️⃣  Exit")
        print("==============================================")
        
        choice = input("Enter your choice (1-4): ")
        
        if choice == "1":
            add_expense()
        elif choice == "2":
            view_expenses()
        elif choice == "3":
            view_total_expense()
        elif choice == "4":
            print("👋 Exiting... Have a great day managing your expenses!")
            break
        else:
            print("❌ Invalid choice. Please enter a number from 1-4.")


# Run the program
if __name__ == "__main__":
    main()

✅ Verified:
• Works perfectly in Python 3.8+
• Creates a file if it doesn't exist
• Handles invalid inputs gracefully
• Tested with multiple entries

5) Output Examples

Example 1: Adding Expense

========== Personal Expense Tracker ==========
1️⃣ Add New Expense
2️⃣ View All Expenses
3️⃣ View Total Expenses
4️⃣ Exit
==============================================
Enter your choice (1-4): 1

--- Add New Expense ---
Enter category (Food, Transport, etc.): Food
Enter amount (in USD): 12.50
Enter short description: Lunch with friends
✅ Expense added successfully!

Example 2: Viewing Expenses

--- View All Expenses ---
Date | Category | Amount($) | Description
-------------------------------------------------------
2025-10-22 | Food | 12.50 | Lunch with friends
2025-10-22 | Transport | 5.00 | Bus ticket

Example 3: Viewing Total

--- Total Expenses ---
💵 Total Spent: $17.50

6) Extension Challenge

🎯 Ideas to make it more advanced

Goal: Enhance your expense tracker with these features:

Use CSV file instead of TXT: Replace the text file with a structured CSV format using the csv module
Add Date Filtering: Allow users to view expenses for a specific month or date range
Visualize Spending: Use Matplotlib or Pandas to generate graphs of spending by category
GUI Version: Build a Tkinter interface for adding/viewing expenses in a table-like view

7) Summary

You have successfully built a Personal Expense Tracker that:

Records and manages financial data
Uses file handling for data persistence
Encourages structured, modular programming

You learned how to:

Create menu-based apps
Write and read data to files
Handle errors and invalid inputs gracefully

💡 "Small habits like tracking expenses lead to big achievements — and you just built a program to make that easier!"

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