Python Programming

Hey Python explorers! 🌟 Ever wish you had a tiny, always‑ready to‑go to‑do list right in your terminal? Let’s build a Command‑line Todo Manager you can finish in one sitting. It’s perfect for beginners because it leans on only the standard library plus one optional, lightweight third‑party helper for nice tables.

What the app does

- Add a task with a short description and a priority (1 = high, 5 = low).
- Show all pending tasks, nicely ordered by priority and creation time.
- Mark a task as done, which moves it out of the active list.
- Persist everything between runs so you never lose a note.

Why it works

- shelve behaves like a dictionary that lives on disk. When you assign db[task_id] = task_dict, Python automatically pickles (serializes) the object and writes it to a file. The next time you open the shelf you get the same data back – no manual file handling needed.
- datetime gives us timestamps. By storing datetime.now() when a task is created we can later sort tasks chronologically, and the strftime method lets us turn those timestamps into human‑readable strings.
- Sorting is just a one‑liner: sorted(tasks, key=lambda t: (t['priority'], t['created'])). The key function tells Python how to compare items, so higher‑priority (lower number) tasks appear first, and ties are broken by the older entry.
- If you want a prettier table, tabulate (install with pip install tabulate) turns a list of dicts into an aligned grid without you writing any formatting code.

Sketch of the code

import shelve
from datetime import datetime

DB_NAME = 'todos.db'          # shelf file on disk
DATE_FMT = '%Y-%m-%d %H:%M'   # how dates appear to the user

def add_task(desc: str, priority: int = 3):
    """Create a new task and store it."""
    with shelve.open(DB_NAME) as db:
        task_id = str(int(time.time() * 1000))   # simple unique key
        db[task_id] = {
            'desc': desc,
            'priority': priority,
            'created': datetime.now(),
            'done': False
        }
    print(f'✅ Task added with ID {task_id}')

def list_tasks():
    """Show all pending tasks, sorted by priority then date."""
    with shelve.open(DB_NAME) as db:
        tasks = [v | {'id': k} for k, v in db.items() if not v['done']]
    tasks.sort(key=lambda t: (t['priority'], t['created']))

    # optional pretty table
    try:
        from tabulate import tabulate
        table = tabulate(
            [[t['id'], t['desc'], t['priority'], t['created'].strftime(DATE_FMT)]
             for t in tasks],
            headers=['ID', 'Description', 'Prio', 'Created'],
            tablefmt='simple')
        print(table)
    except ImportError:
        for t in tasks:
            print(f"{t['id']}: [{t['priority']}] {t['desc']} (added {t['created']:{DATE_FMT}})")

def complete_task(task_id: str):
    """Mark a task as done."""
    with shelve.open(DB_NAME, writeback=True) as db:
        if task_id in db:
            db[task_id]['done'] = True
            print(f'✔️ Task {task_id} completed!')
        else:
            print('❌ No such task.')

# ----------------------------------------------------------------------
# Quick interactive demo (run the file and follow the prompts)
if __name__ == '__main__':
    import time
    while True:
        cmd = input('\n[t] Add  [l] List  [c] Complete  [q] Quit > ').strip().lower()
        if cmd == 't':
            d = input('Description: ')
            p = int(input('Priority (1‑5, 1=high): ') or 3)
            add_task(d, p)
        elif cmd == 'l':
            list_tasks()
        elif cmd == 'c':
            tid = input('Task ID to finish: ')
            complete_task(tid)
        elif cmd == 'q':
            break

How to run it

(continued below 👇)

7 viewsRams Poster, 12:00