Day 10: Practical Projects

What You'll Learn Today

On this final day, we'll apply everything we've learned to build practical projects.

• Project 1: TODO App (CLI)
• Project 2: Weather Information Tool
• Guide to Next Steps

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Project 1: TODO App (CLI)

Build a simple command-line TODO application.

Requirements

• Add tasks
• List tasks
• Mark tasks as complete
• Delete tasks
• Data persistence (JSON)

Complete Code

#!/usr/bin/env python3
"""
Simple TODO App
Usage: python todo.py [command] [arguments]
"""

import json
import argparse
from pathlib import Path
from datetime import datetime

# Data file path
TODO_FILE = Path.home() / '.todo.json'

def load_todos():
    """Load TODO list"""
    if not TODO_FILE.exists():
        return []
    try:
        with open(TODO_FILE, 'r', encoding='utf-8') as f:
            return json.load(f)
    except json.JSONDecodeError:
        return []

def save_todos(todos):
    """Save TODO list"""
    with open(TODO_FILE, 'w', encoding='utf-8') as f:
        json.dump(todos, f, indent=2)

def add_todo(title):
    """Add a task"""
    todos = load_todos()
    todo = {
        'id': len(todos) + 1,
        'title': title,
        'done': False,
        'created_at': datetime.now().isoformat()
    }
    todos.append(todo)
    save_todos(todos)
    print(f"Added task: {title}")

def list_todos(show_all=False):
    """Display task list"""
    todos = load_todos()
    if not todos:
        print("No tasks found")
        return

    print("\nTODO List:")
    print("-" * 50)
    for todo in todos:
        if not show_all and todo['done']:
            continue
        status = "x" if todo['done'] else " "
        print(f"  [{status}] {todo['id']}. {todo['title']}")
    print("-" * 50)

def complete_todo(todo_id):
    """Mark task as complete"""
    todos = load_todos()
    for todo in todos:
        if todo['id'] == todo_id:
            todo['done'] = True
            save_todos(todos)
            print(f"Completed: {todo['title']}")
            return
    print(f"Task not found: ID {todo_id}")

def delete_todo(todo_id):
    """Delete a task"""
    todos = load_todos()
    for i, todo in enumerate(todos):
        if todo['id'] == todo_id:
            removed = todos.pop(i)
            save_todos(todos)
            print(f"Deleted: {removed['title']}")
            return
    print(f"Task not found: ID {todo_id}")

def main():
    parser = argparse.ArgumentParser(description='Simple TODO App')
    subparsers = parser.add_subparsers(dest='command', help='Commands')

    # add command
    add_parser = subparsers.add_parser('add', help='Add a task')
    add_parser.add_argument('title', help='Task title')

    # list command
    list_parser = subparsers.add_parser('list', help='List tasks')
    list_parser.add_argument('-a', '--all', action='store_true', help='Show completed')

    # done command
    done_parser = subparsers.add_parser('done', help='Complete a task')
    done_parser.add_argument('id', type=int, help='Task ID')

    # delete command
    delete_parser = subparsers.add_parser('delete', help='Delete a task')
    delete_parser.add_argument('id', type=int, help='Task ID')

    args = parser.parse_args()

    if args.command == 'add':
        add_todo(args.title)
    elif args.command == 'list':
        list_todos(args.all)
    elif args.command == 'done':
        complete_todo(args.id)
    elif args.command == 'delete':
        delete_todo(args.id)
    else:
        parser.print_help()

if __name__ == '__main__':
    main()

Usage

# Add tasks
python todo.py add "Study Python"
python todo.py add "Go shopping"

# List tasks
python todo.py list
python todo.py list --all  # Include completed

# Complete a task
python todo.py done 1

# Delete a task
python todo.py delete 2

Learning Points

flowchart TB
    subgraph Concepts["Concepts Used"]
        A["argparse: CLI argument parsing"]
        B["json: Data persistence"]
        C["pathlib: File paths"]
        D["datetime: Date/time handling"]
        E["functions: Code organization"]
    end

    style Concepts fill:#3b82f6,color:#fff

---

Project 2: Weather Information Tool

A tool that fetches weather information using a Web API.

Requirements

• Get weather by city name
• Display current temperature and weather
• Error handling

Complete Code

#!/usr/bin/env python3
"""
Weather Information Tool
Uses Open-Meteo API (no API key required)
"""

import argparse
import urllib.request
import urllib.error
import json
from dataclasses import dataclass

# Major city coordinates
CITIES = {
    'tokyo': {'lat': 35.6762, 'lon': 139.6503, 'name': 'Tokyo'},
    'osaka': {'lat': 34.6937, 'lon': 135.5023, 'name': 'Osaka'},
    'new_york': {'lat': 40.7128, 'lon': -74.0060, 'name': 'New York'},
    'london': {'lat': 51.5074, 'lon': -0.1278, 'name': 'London'},
    'paris': {'lat': 48.8566, 'lon': 2.3522, 'name': 'Paris'},
    'sydney': {'lat': -33.8688, 'lon': 151.2093, 'name': 'Sydney'},
    'berlin': {'lat': 52.5200, 'lon': 13.4050, 'name': 'Berlin'},
    'singapore': {'lat': 1.3521, 'lon': 103.8198, 'name': 'Singapore'},
}

# Weather code descriptions
WEATHER_CODES = {
    0: 'Clear sky',
    1: 'Mainly clear',
    2: 'Partly cloudy',
    3: 'Overcast',
    45: 'Foggy',
    48: 'Depositing rime fog',
    51: 'Light drizzle',
    53: 'Moderate drizzle',
    55: 'Dense drizzle',
    61: 'Slight rain',
    63: 'Moderate rain',
    65: 'Heavy rain',
    71: 'Slight snow',
    73: 'Moderate snow',
    75: 'Heavy snow',
    80: 'Slight rain showers',
    81: 'Moderate rain showers',
    82: 'Violent rain showers',
    95: 'Thunderstorm',
    96: 'Thunderstorm with hail',
    99: 'Thunderstorm with heavy hail',
}

@dataclass
class Weather:
    """Weather information container"""
    city: str
    temperature: float
    weather_code: int
    humidity: int
    wind_speed: float

    @property
    def weather_description(self):
        return WEATHER_CODES.get(self.weather_code, 'Unknown')

    def __str__(self):
        return f"""
Weather in {self.city}
========================
  Conditions: {self.weather_description}
  Temperature: {self.temperature}C
  Humidity: {self.humidity}%
  Wind Speed: {self.wind_speed} km/h
========================
"""

def fetch_weather(city_key):
    """Fetch weather information"""
    if city_key not in CITIES:
        raise ValueError(f"Unknown city: {city_key}")

    city = CITIES[city_key]
    url = (
        f"https://api.open-meteo.com/v1/forecast?"
        f"latitude={city['lat']}&longitude={city['lon']}"
        f"&current=temperature_2m,weather_code,relative_humidity_2m,wind_speed_10m"
    )

    try:
        with urllib.request.urlopen(url, timeout=10) as response:
            data = json.loads(response.read().decode())
    except urllib.error.URLError as e:
        raise ConnectionError(f"Failed to connect to API: {e}")
    except json.JSONDecodeError:
        raise ValueError("Failed to parse API response")

    current = data.get('current', {})
    return Weather(
        city=city['name'],
        temperature=current.get('temperature_2m', 0),
        weather_code=current.get('weather_code', 0),
        humidity=current.get('relative_humidity_2m', 0),
        wind_speed=current.get('wind_speed_10m', 0)
    )

def list_cities():
    """Display available cities"""
    print("\nAvailable Cities:")
    print("-" * 30)
    for key, info in CITIES.items():
        print(f"  {key:12} : {info['name']}")
    print("-" * 30)

def main():
    parser = argparse.ArgumentParser(description='Weather Information Tool')
    parser.add_argument('city', nargs='?', help='City name (e.g., tokyo, london)')
    parser.add_argument('-l', '--list', action='store_true', help='List available cities')

    args = parser.parse_args()

    if args.list:
        list_cities()
        return

    if not args.city:
        parser.print_help()
        list_cities()
        return

    city_key = args.city.lower()

    try:
        weather = fetch_weather(city_key)
        print(weather)
    except ValueError as e:
        print(f"Error: {e}")
        list_cities()
    except ConnectionError as e:
        print(f"Connection Error: {e}")
    except Exception as e:
        print(f"Unexpected Error: {e}")

if __name__ == '__main__':
    main()

Usage

# Get weather for a city
python weather.py tokyo
python weather.py london
python weather.py new_york

# List available cities
python weather.py --list

Learning Points

Concept	Usage
urllib	HTTP requests
dataclass	Data structuring
Exception handling	Error handling
Dictionaries	City data management
f-strings	Output formatting

---

Project Extension Ideas

TODO App Extensions

1. Priority levels: high, medium, low
2. Due dates: Set deadlines
3. Categories: Work, personal, shopping tags
4. Search: Find tasks by title
5. Export: CSV/Markdown format output

Weather App Extensions

1. Weekly forecast: 7-day weather
2. Multiple cities: Compare at once
3. Graphs: Text-based temperature charts
4. Alerts: Notifications for conditions
5. Caching: Cache API responses

---

Completing the 10-Day Journey

Congratulations! You've learned Python from basics to practical application over 10 days.

What You've Learned

flowchart TB
    subgraph Basics["Basics (Day 1-3)"]
        A["Environment Setup"]
        B["Variables & Types"]
        C["Control Flow"]
    end

    subgraph DataStructures["Data Structures (Day 4)"]
        D["Lists & Tuples"]
        E["Dicts & Sets"]
    end

    subgraph Functions["Functions & OOP (Day 5-6)"]
        F["Function Definition"]
        G["Classes & Inheritance"]
    end

    subgraph Advanced["Advanced (Day 7-9)"]
        H["Modules"]
        I["File Operations"]
        J["Standard Library"]
    end

    subgraph Practice["Practice (Day 10)"]
        K["Project Development"]
    end

    Basics --> DataStructures --> Functions --> Advanced --> Practice

    style Basics fill:#3b82f6,color:#fff
    style DataStructures fill:#8b5cf6,color:#fff
    style Functions fill:#22c55e,color:#fff
    style Advanced fill:#f59e0b,color:#fff
    style Practice fill:#ef4444,color:#fff

---

Next Steps

Web Development

# Flask example
from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello():
    return 'Hello, World!'

• Flask: Lightweight web framework
• Django: Full-stack web framework
• FastAPI: High-performance API framework

Data Analysis

# pandas example
import pandas as pd

df = pd.read_csv('data.csv')
print(df.describe())

• pandas: Data analysis library
• NumPy: Numerical computing library
• Matplotlib: Graphing library

Machine Learning

# scikit-learn example
from sklearn.linear_model import LinearRegression

model = LinearRegression()
model.fit(X_train, y_train)

• scikit-learn: Machine learning library
• TensorFlow/PyTorch: Deep learning frameworks

Automation

• Selenium: Browser automation
• Beautiful Soup: Web scraping
• Schedule: Task scheduling

---

Learning Resources

Official Documentation

• Python Official Tutorial
• Python Standard Library

Online Learning

• Real Python
• Python.org

Books

• "Python Crash Course" - Eric Matthes
• "Fluent Python" - Luciano Ramalho
• "Effective Python" - Brett Slatkin

Communities

• Stack Overflow
• Reddit r/learnpython
• Python Discord

---

Summary

Day	Topic	Skills Acquired
1	Welcome to Python	Setup, Hello World
2	Variables & Types	int, str, bool, conversion
3	Control Flow	if, for, while
4	Data Structures	list, dict, set, tuple
5	Functions	def, lambda, decorators
6	OOP	class, inheritance, encapsulation
7	Modules	import, pip, venv
8	Files & Exceptions	open, try-except
9	Standard Library	collections, re, logging
10	Practical Projects	Application development

Final Words

Programming is a journey of continuous learning. Use the foundation from this course to explore areas that interest you.

"Write code 100 times rather than read about it once"

Keep coding and learning! Don't fear failure, and challenge yourself with many projects!

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References

• Python Official Site
• PyPI - Python Package Index
• GitHub - Awesome Python
• Python Weekly

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Congratulations! You've completed the Python Fundamentals Course! 🎉