beginner

To-Do Application

A command-line to-do list application with add, view, complete, and delete functionality with file persistence.

Features

Add/remove tasks
Mark tasks as complete
File-based persistence
Priority levels
List all tasks

Technologies Used

File HandlingListsDictionariesFunctionsJSON

Explanation

Tasks are stored as dictionaries in a list and saved to a JSON file for persistence. Users can add, view, complete, and delete tasks through a menu-driven interface.

Source Code

import json
import os
from datetime import datetime

TASKS_FILE = "tasks.json"

def load_tasks():
    if os.path.exists(TASKS_FILE):
        with open(TASKS_FILE, "r") as f:
            return json.load(f)
    return []

def save_tasks(tasks):
    with open(TASKS_FILE, "w") as f:
        json.dump(tasks, f, indent=2)

def add_task(tasks):
    title = input("Task title: ")
    priority = input("Priority (high/medium/low): ").lower()
    task = {
        "id": len(tasks) + 1,
        "title": title,
        "priority": priority,
        "completed": False,
        "created": datetime.now().strftime("%Y-%m-%d %H:%M")
    }
    tasks.append(task)
    save_tasks(tasks)
    print(f"✅ Task '{title}' added!")

def view_tasks(tasks):
    if not tasks:
        print("No tasks found!")
        return
    print("\n--- Your Tasks ---")
    for t in tasks:
        status = "✓" if t["completed"] else "○"
        print(f"  [{status}] {t['id']}. {t['title']} ({t['priority']}) - {t['created']}")
    print()

def complete_task(tasks):
    view_tasks(tasks)
    task_id = int(input("Enter task ID to complete: "))
    for t in tasks:
        if t["id"] == task_id:
            t["completed"] = True
            save_tasks(tasks)
            print(f"✅ Task '{t['title']}' completed!")
            return
    print("Task not found!")

def delete_task(tasks):
    view_tasks(tasks)
    task_id = int(input("Enter task ID to delete: "))
    tasks[:] = [t for t in tasks if t["id"] != task_id]
    save_tasks(tasks)
    print("🗑️ Task deleted!")

def main():
    print("=== To-Do Application ===")
    tasks = load_tasks()

    while True:
        print("\n1. Add Task  2. View Tasks  3. Complete  4. Delete  5. Exit")
        choice = input("Choose: ")
        if choice == "1": add_task(tasks)
        elif choice == "2": view_tasks(tasks)
        elif choice == "3": complete_task(tasks)
        elif choice == "4": delete_task(tasks)
        elif choice == "5":
            print("Goodbye!")
            break

main()