FAQ

Is uv absolutely necessary to use usethis?

No, although it is highly recommended for new projects, since it is a modern and easy-to-use tool for managing Python projects. If you don't have uv installed, usethis will automatically avoid using it. See Backends for more details on how usethis selects and uses a package manager backend.

If you have uv installed but you want to avoid using it for a specific project, you should use the --backend=none option when running usethis commands. usethis also supports Poetry as a backend — see Backends for details.

There is another reason to use uv, which is to provide the uvx command for running usethis. This provides an easy way to use usethis without needing to know technical details about Python virtual environments.

What if I'm using Poetry for my project?

Poetry is fully supported as a backend. If you're using Poetry, usethis will automatically detect this and use the Poetry backend to install and uninstall dependencies, configure dependency groups, and give you Poetry-specific instructions. See Backends for more details on how the backend is selected and what each backend provides.

If I add a tool which is already configured, why does additional configuration get added?

Some configuration is necessary to ensure smooth integrations with other tools. However, usethis will never overwrite existing configuration options, only add new ones, i.e. override defaults. If you want to rely on default values and prevent usethis from overwriting them, you can set a configuration entry explicitly to the default value in your configuration file.

Why does usethis make formatting changes to my config files?

When modifying files like pyproject.toml and .pre-commit-config.yaml, usethis attempts to preserve the original formatting as much as possible.

However, there are some known limitations for YAML files. In Python, there is currently no YAML parser with pure round-trip support. The closest is ruamel.yaml, but it has some known limitations. If you find that usethis has modified your files in a way that you did not expect, please open an issue on the usethis GitHub repository, and if necessary the issue can be escalated to the ruamel.yaml repository on SourceForge, or another appropriate repository.

Is this a Python port of usethis in R?

No. usethis-python was built from the ground up, and specializes in servicing the Python ecosystem. It is definitely inspired by R's usethis package, but it is not a port. There are too many fundamental differences between the two languages' ecosystems and communities to make a port feasible.

One major difference is that usethis-python provides a Command Line Interface (CLI) rather than a collection of functions - again this is due to the differences in the language communities, where Python developers are more likely to use a CLI. Actually, under the hood, usethis-python does use a collection of functions, but these are not currently guaranteed to be stable or well-documented.