Python Bliss

A brief description of installing Python Packages Using Pip and Virtual Environments for WINDOWS.

Installing pip

pip is the reference Python package manager. It’s used to install and update packages. You’ll need to make sure you have the latest version of pip installed.

The Python installers for Windows include pip. You can make sure that pip is up-to-date by running:

  py -m pip install --upgrade pip
  py -m pip --version

Afterwards, you should have the latest version of pip:

  pip 23.3 from c:\python39\lib\site-packages 
  (Python 3.12)

Creating a virtual environment

'venv' (for 'Python 3') and 'virtualenv' (for 'Python 2') allow you to manage distinct package installations for various projects. They essentially allow you to construct a "virtual" isolated Python installation and install packages into that virtual installation. When switching projects, you may simply establish a new virtual environment and not worry about breaking the packages installed in the previous environments. It is usually suggested to use a virtual environment when building Python applications.

To create a virtual environment, go to your project’s directory and run venv. If you are using Python 2, replace venv with virtualenv in the below commands.

  py -m venv env_name

The second argument is the location to create the virtual environment.

venv will create a virtual Python installation in the env_name folder.

Activating a virtual environment

Before you can start installing or using packages in your virtual environment you’ll need to activate it. Activating a virtual environment will put the virtual environment-specific python and pip executables into your shell’s PATH.

  .\envAuto\Scripts\activate

You can confirm you’re in the virtual environment by checking the location of your Python interpreter:

  where python

It should be in the env_name directory:

  ...\env\Scripts\python.exe

As long as your virtual environment is activated pip will install packages into that specific environment and you’ll be able to import and use packages in your Python application.

Installing Packages

To install a package, use the following command:

  pip install package_name

Installing Specific Versions

Specify the version using the following syntax:

  pip install package_name==version_number

Upgrading Packages

Keep packages up-to-date with:

  pip install --upgrade package_name

Uninstalling Packages

Remove a package with:

  pip uninstall package_name

Displaying Installed Packages

Easily view the installed packages within your environment by using the following command:

  pip list

This command provides a clear and concise list of all installed Python packages, along with their respective versions, giving you a quick overview of the components within your development environment.

Freezing Requirements

Capture the exact versions of installed packages for reproducibility:

  pip freeze > requirements.txt

Installing Requirements from a File

To replicate the environment, use:

  py -m pip install -r requirements.txt

Deactivating the Virtual Environment

Simply use:

  deactivate

Note

You should exclude your virtual environment directory from your version control system using .gitignore.