Release Date: May 31, 2022

This is a beta preview of Python 3.11

Python 3.11 is still in development. 3.11.0b2 is the second of four planned beta release previews. Beta release previews are intended to give the wider community the opportunity to test new features and bug fixes and to prepare their projects to support the new feature release.

We strongly encourage maintainers of third-party Python projects to test with 3.11 during the beta phase and report issues found to the Python bug tracker as soon as possible. While the release is planned to be feature complete entering the beta phase, it is possible that features may be modified or, in rare cases, deleted up until the start of the release candidate phase (Monday, 2021-08-02). Our goal is have no ABI changes after beta 4 and as few code changes as possible after 3.11.0rc1, the first release candidate. To achieve that, it will be extremely important to get as much exposure for 3.11 as possible during the beta phase.

Please keep in mind that this is a preview release and its use is not recommended for production environments.

Note: There is a known issue with pytest and this release. If you get failures running pytest you can work around temporarily the problem by adding --assert=plain to the pytest command line invocation

Major new features of the 3.11 series, compared to 3.10

Some of the new major new features and changes in Python 3.11 are:

General changes

• PEP 657 -- Include Fine-Grained Error Locations in Tracebacks
• PEP 654 -- Exception Groups and except*
• PEP 680-- tomllib: Support for Parsing TOML in the Standard Library
• PEP 681-- Data Class Transforms
• bpo-46752-- Introduce task groups to asyncio
• bpo-433030 -- Atomic grouping ((?>...)) and possessive quantifiers (*+, ++, ?+, {m,n}+) are now supported in regular expressions.
• The Faster Cpython Project is already yielding some exciting results. Python 3.11 is up to 10-60% faster than Python 3.10. On average, we measured a 1.22x speedup on the standard benchmark suite. See Faster CPython for details.

Typing and typing language changes

• PEP 673 -- Self Type
• PEP 646-- Variadic Generics
• PEP 675-- Arbitrary Literal String Type
• PEP 655-- Marking individual TypedDict items as required or potentially-missing

(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release of Python 3.11 will be 3.11.0b3, currently scheduled for Thursday, 2022-06-16.

More resources

• Online Documentation
• PEP 664, 3.11 Release Schedule
• Report bugs at https://bugs.python.org.
• Help fund Python and its community.

And now for something completely different

The Planck time is the time required for light to travel a distance of 1 Planck length in a vacuum, which is a time interval of approximately 5.39*10^(−44) s. No current physical theory can describe timescales shorter than the Planck time, such as the earliest events after the Big Bang, and it is conjectured that the structure of time breaks down on intervals comparable to the Planck time. While there is currently no known way to measure time intervals on the scale of the Planck time, researchers in 2020 found that the accuracy of an atomic clock is constrained by quantum effects on the order of the Planck time, and for the most precise atomic clocks thus far they calculated that such effects have been ruled out to around 10^−33 s, or 10 orders of magnitude above the Planck scale.

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