  In this research, we provide a comprehensive empirical summary of the Python
Package Repository, PyPI, including both package metadata and source code
covering 178,592 packages, 1,745,744 releases, 76,997 contributors, and
156,816,750 import statements. We provide counts and trends for packages,
releases, dependencies, category classifications, licenses, and package
imports, as well as authors, maintainers, and organizations. As one of the
largest and oldest software repositories as of publication, PyPI provides
insight not just into the Python ecosystem today, but also trends in software
development and licensing more broadly over time. Within PyPI, we find that the
growth of the repository has been robust under all measures, with a compound
annual growth rate of 47% for active packages, 39% for new authors, and 61% for
new import statements over the last 15 years. As with many similar social
systems, we find a number of highly right-skewed distributions, including the
distribution of releases per package, packages and releases per author, imports
per package, and size per package and release. However, we also find that most
packages are contributed by single individuals, not multiple individuals or
organizations. The data, methods, and calculations herein provide an anchor for
public discourse on PyPI and serve as a foundation for future research on the
Python software ecosystem.
