In this section, we will guide you through the process of setting up your development environment for Flask. This includes installing Python, setting up a virtual environment, and installing Flask. By the end of this section, you will have a fully functional environment ready for Flask development.

Flask is a Python web framework, so the first step is to ensure you have Python installed on your machine.

1. Download the latest version of Python from the official website.
2. Run the installer and make sure to check the box that says "Add Python to PATH".
3. Follow the installation instructions.

1. Open Terminal.

2. Use Homebrew to install Python (if you don't have Homebrew, install it from here):

   brew install python
   

1. Open Terminal.

2. Use your package manager to install Python. For example, on Ubuntu:

   sudo apt update
   sudo apt install python3 python3-pip
   

A virtual environment is a self-contained directory that contains a Python installation for a particular version of Python, plus a number of additional packages. Using virtual environments is a good practice to avoid conflicts between dependencies of different projects.

1. Open your terminal or command prompt.

2. Navigate to your project directory or create a new one:

   mkdir my_flask_app
   cd my_flask_app
   

3. Create a virtual environment:

   python -m venv venv
   

• Windows:

  venv\Scripts\activate
  

• macOS/Linux:

  source venv/bin/activate
  

You should see (venv) at the beginning of your terminal prompt, indicating that the virtual environment is active.

With the virtual environment activated, you can now install Flask using pip.

To verify the installation, you can run:

You should see the version of Flask that was installed.

Let's create a simple Flask application to ensure everything is set up correctly.

1. Create a new file named app.py in your project directory:

   touch app.py
   

2. Open app.py in your favorite text editor and add the following code:

   from flask import Flask
   
   app = Flask(__name__)
   
   @app.route('/')
   def hello_world():
       return 'Hello, World!'
   
   if __name__ == '__main__':
       app.run(debug=True)
   

3. Save the file and run the application:

   python app.py
   

4. Open your web browser and navigate to http://127.0.0.1:5000/. You should see "Hello, World!" displayed on the page.

In this section, you have learned how to:

• Install Python on your operating system.
• Set up a virtual environment to manage your project's dependencies.
• Install Flask within the virtual environment.
• Create and run a basic Flask application.

With your development environment set up, you are now ready to dive deeper into Flask and start building more complex applications. In the next section, we will create your first Flask application and explore the structure of a typical Flask project.