Exercise - Create a package

  • 2 minutes

In this exercise, you'll learn how to use virtual environments as a way to not affect globally installed packages or other programs running on your machine.

Create a virtual environment

Create a virtual environment by using venv.

  1. Open a new console window and run the following command:

    python -m venv env

    You now have an env directory created in your terminal.

  2. To activate the virtual environment, run the following command on Windows:

    .\env\Scripts\activate

    Or, this command on Linux, WSL or macOS:

    source env/bin/activate

    You now see (env) in your terminal. That means you've activated your virtual environment and isolated yourself from the rest of your machine.

Install a library

Now that you're inside your virtual environment, you can install a library and know that the library will exist only in the virtual environment.

  1. Run pip freeze to see installed libraries in your environment:

    pip freeze

    You should get no response. Next, let's see how the output of pip freeze changes when you add a library (a package).

  2. Run pip install to install a library:

    pip install python-dateutil

    A large output of text says it's installing your library, and it should end with the following sentence:

    Successfully installed python-dateutil-2.8.2 six-1.16.0

  3. Rerun pip freeze to see how your list of libraries has changed:

    pip freeze

    Now you should see the following list:

    python-dateutil==2.8.2
six==1.16.0

Deactivate a virtual environment

So far, you've created a virtual environment and added a package to it. However, you might be working on several Python projects and need to change between them. To do that, you need step out of (deactivate) your virtual environment.

Run the deactivate command:

deactivate

Note how your terminal prompt changes from (env) to how it looked before.

Congratulations! You've managed to successfully create and use a virtual environment.