The bidirectional mapping library for Python.

• Depended on by Google, Venmo, CERN, Baidu, Tencent, and teams across the world since 2009
• Familiar, Pythonic APIs that are carefully designed for safety, simplicity, flexibility, and ergonomics
• Lightweight, with no runtime dependencies outside Python's standard library
• Implemented in concise, well-factored, fully type-hinted Python code that is optimized for running efficiently as well as for long-term maintenance and stability (not to mention joy :)
• Extensively documented
• 100% test coverage running continuously across all supported Python versions

pip install bidict

>>> from bidict import bidict
>>> element_by_symbol = bidict({'H': 'hydrogen'})
>>> element_by_symbol['H']
'hydrogen'
>>> element_by_symbol.inverse['hydrogen']
'H'

For more usage documentation, head to the intro [1] and proceed from there.

Enterprise-level support for bidict can be obtained via the Tidelift subscription or by contacting me directly.

I have a US-based LLC set up for invoicing, and I have 15 years of professional experience delivering software and support to companies successfully.

You can also sponsor my work through platforms like GitHub Sponsors. See the Sponsoring section below for details, including rationale and examples of companies supporting the open source projects they depend on.

Please search through already-asked questions and answers in GitHub Discussions and the issue tracker in case your question has already been addressed.

Otherwise, please feel free to start a new discussion or create a new issue on GitHub, or ask in the bidict chatroom for voluntary community support.

If you use bidict, and especially if your usage or your organization is significant in some way, please let me know in any of the following ways:

• star bidict on GitHub
• post in GitHub Discussions
• leave a message in the chat room
• email me

For bidict release notes, see the changelog. [2]

Watch bidict releases on GitHub to be notified when new versions of bidict are published. Click the "Watch" dropdown, choose "Custom", and then choose "Releases".

One of the best things about bidict is that it touches a surprising number of interesting Python corners, especially given its small size and scope.

Check out learning-from-bidict [3] if you're interested in learning more.

I have been bidict's sole maintainer and active contributor since I started the project ~15 years ago.

Your help would be most welcome! See the contributors-guide [4] for more information.

Bidict is the product of thousands of hours of my unpaid work over the ~15 years that I've been the sole maintainer.

If bidict has helped you or your company accomplish your work, please sponsor my work through GitHub and/or ask your company to do the same.

Choose a tier and GitHub handles everything else. Your GitHub sponsorship will automatically go on the same bill you already have set up with GitHub, so after the one-click signup, there's nothing else to do.

See the following for rationale and examples of companies supporting the open source projects they depend on in this manner:

• https://engineering.indeedblog.com/blog/2019/07/foss-fund-six-months-in/
• https://engineering.atspotify.com/2022/04/announcing-the-spotify-foss-fund/
• https://blog.sentry.io/2021/10/21/we-just-gave-154-999-dollars-and-89-cents-to-open-source-maintainers

You can also support my work through Gumroad or PayPal, or through a support engagement with my LLC. See Enterprise Support above for details.

If you're viewing this on https://bidict.readthedocs.io, note that multiple versions of the documentation are available, and you can choose a different version using the popup menu at the bottom-right. Please make sure you're viewing the version of the documentation that corresponds to the version of bidict you'd like to use.

If you're viewing this on GitHub, PyPI, or some other place that can't render and link this documentation properly and are seeing broken links, try these alternate links instead: