Overview of the Standard Python Package Manager, PIP.
Introduction
The standard Python package manager is pip. It is ideal for quickly starting Python projects, like simple scripts or small projects with few dependencies. While capable of handling larger projects, tools like poetry are ideal for larger projects with complex dependencies.
The following notes assume:
Python 3
MacOS
An alias in bash profile to map python to python3.
Setup
The following is a step-by-step process for setting up a virtual environment in my-project and installing dependencies in it with pip.
cd into your project directory.
cd my-project
Create the virtual environment named env.
python -m venv env
Activate the virtual environment.
source env/bin/activate
Install dependencies.
pip install <PACKAGE_NAME>
Commands
The following is a list of common commands used when managing a project with pip.
Activate Virtual Environment
source env/bin/activate
Deactivate Virtual Environment
deactivate
Uninstall a Package
pip uinstall <PACKAGE_NAME>
List Installed Packages
pip freeze
Create a requirements.txt File
pip freeze > requirements.txt
Install Packages from a requirements.txt File
pip install -r requirements.txt
Pitfalls & Solutions
The following are common pitfalls when working with pip and their solutions.
I installed packages without activating my virtual environment.
To uninstall packages from your machine using the requirements.txt file in your project, make sure your virtual environment is not activated and run the following command:
pip uninstall -r requirements.txt
To uninstall all global Python packages from your machine, make sure your virtual environment is not activated and run the following command:
pip freeze | xargs pip uninstall -y
How do I pin the versions of my project's dependencies?
To prevent dependency conflicts, it is recommended to create a requirements.txt file with pinned package versions. The following command is a way to automatically create a requirements.txt file from the packages installed in your virtual environment:
pip freeze > requirements.txt
Can I disable pip when there is no virtual environment activated?
Yes. To require a virtual environment to be active when running pip commands, a config file can be used.
Run the following command to set require-virtualenv to True.
pip config set global.require-virtualenv True
Now, the contents of ~/.config/pip/pip.conf should be:
[global]
require-virtualenv = True
If you ever need to get around this requirement, you can either temporarily set require-virtualenv to False, or prepend your pip commands as follows:
