Creating a Virtual Environment

When using Raspberry Pi or similar devices, it is recommended to install packages with pip in a virtual environment. It offers dependency isolation, increases system security, maintains system cleanliness, and facilitates project migration and sharing, simplifying dependency management. These benefits make virtual environments an extremely important and useful tool in Python development.

Below are the steps to create a virtual environment:

1. Create a virtual environment

Firstly, you need to ensure that your system has Python installed. Python version 3.3 and later come with the venv module to create virtual environments, eliminating the need for separate installation. If you are using Python 2 or a version before Python 3.3, you will need to install virtualenv.

  • For Python 3:

Python 3.3 and later versions can directly use the venv module:

python3 -m venv myenv

This will create a virtual environment named myenv in the current directory.

  • For Python 2:

If you are still using Python 2, you first need to install virtualenv:

pip install virtualenv

Then, create a virtual environment:

virtualenv myenv

This also creates a virtual environment named myenv in the current directory.

2. Activating the Virtual Environment

After creating the virtual environment, you need to activate it for use.

Note

Each time you restart the Raspberry Pi, or open a new terminal, you will need to run the following command again to activate the virtual environment.

source myenv/bin/activate

Once the virtual environment is activated, you will see the environment name before the command line prompt, indicating you are working within the virtual environment.

3. Installing Dependencies

With the virtual environment activated, you can use pip to install the required dependencies. For example:

pip install requests

This will install the requests library into the current virtual environment, rather than the global environment. This step only needs to be done once.

4. Exiting the Virtual Environment

When you have completed your work and wish to exit the virtual environment, simply run:

deactivate

This will return you to the system’s global Python environment.

5. Deleting the Virtual Environment

If you no longer need a particular virtual environment, you can simply delete the directory containing the virtual environment:

rm -rf myenv