### **Day 27: Introduction to Web Development**
Web development involves creating websites and web applications. Python can be used for web development with the help of web frameworks like Flask or Django.

- **Understanding Web Development:**
  - Web development involves designing and building websites or web applications that are accessible through web browsers.
  - It encompasses both the front-end (user interface) and back-end (server-side) development.

### **Day 28: Flask - Creating a Basic Web Application**
Flask is a lightweight web framework for Python. You can create a basic web application with Flask.

- **Getting Started with Flask:**
  - Install Flask using `pip install flask`.
  - Create a Flask application and define routes.
  - Use decorators like `@app.route('/')` to map URLs to view functions.
  - Start the development server using `app.run()`.

**Example of a basic Flask web application:**
```python
from flask import Flask

app = Flask(__name__)

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

if __name__ == '__main__':
    app.run()
```

### **Day 29: Flask - Adding Routes and Templates**
Flask uses routes to map URLs to view functions. You can use templates to generate dynamic HTML content.

- **Adding Routes and Templates:**
  - Define multiple routes for different URLs.
  - Use the `render_template` function to render HTML templates.
  - Pass data from the view function to the template.

**Example of adding routes and using templates in Flask:**
```python
from flask import Flask, render_template

app = Flask(__name__)

@app.route('/')
def index():
    return 'Home Page'

@app.route('/about')
def about():
    return 'About Us'

@app.route('/contact')
def contact():
    return 'Contact Us'

@app.route('/profile/<username>')
def profile(username):
    return render_template('profile.html', username=username)

if __name__ == '__main__':
    app.run()
```

### **Day 30: Flask - Handling Forms and Data**
Web applications often require handling user input through forms. You can use Flask to create forms and handle form data.

- **Handling Forms in Flask:**
  - Create HTML forms with input fields.
  - Use the `request` object in Flask to access form data.
  - Handle form submissions and process user input.

**Example of handling forms in Flask:**
```python
from flask import Flask, render_template, request

app = Flask(__name__)

@app.route('/')
def index():
    return render_template('index.html')

@app.route('/submit', methods=['POST'])
def submit():
    if request.method == 'POST':
        name = request.form['name']
        email = request.form['email']
        return f'Thank you, {name}, for submitting your email: {email}'

if __name__ == '__main__':
    app.run()
```

Web development is a vast field, and Flask is an excellent starting point for building web applications with Python. However, for more extensive and feature-rich applications, you may consider learning Django, another popular Python web framework. These examples provide a foundation for creating web applications and handling user interactions using Flask. You can continue to explore and expand your web development skills from here.