Python 3.10

New syntax features Status

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New features in the standard library

The :class:`int` type has a new method :meth:`int.bit_count`, returning the number of ones in the binary expansion of a given integer, also known as the population count.

The views returned by :meth:`dict.keys`, :meth:`dict.values` and :meth:`dict.items` now all have a mapping attribute that gives a :class:`types.MappingProxyType` object wrapping the original dictionary.

:func:`zip` function now has an optional strict flag, used to require that all the iterables have an equal length.

Builtin and extension functions that take integer arguments no longer accept :class:`~decimal.Decimal`s, :class:`~fractions.Fraction`s and other objects that can be converted to integers only with a loss (e.g. that have the :meth:`~object.__int__` method but do not have the :meth:`~object.__index__` method).

If :func:`object.__ipow__` returns :const:`NotImplemented`, the operator will correctly fall back to :func:`object.__pow__` and :func:`object.__rpow__` as expected.

Assignment expressions can now be used unparenthesized within set literals and set comprehensions, as well as in sequence indexes (but not slices).

Functions have a new __builtins__ attribute which is used to look for builtin symbols when a function is executed, instead of looking into __globals__['__builtins__']. The attribute is initialized from __globals__["__builtins__"] if it exists, else from the current builtins.

Two new builtin functions -- :func:`aiter` and :func:`anext` have been added to provide asynchronous counterparts to :func:`iter` and :func:`next`, respectively.

Static methods (:func:`@staticmethod <staticmethod>`) and class methods (:func:`@classmethod <classmethod>`) now inherit the method attributes (__module__, __name__, __qualname__, __doc__, __annotations__) and have a new __wrapped__ attribute. Moreover, static methods are now callable as regular functions.

Annotations for complex targets (everything beside simple name targets defined by Class and module objects now lazy-create empty annotations dicts on demand. The annotations dicts are stored in the object’s __dict__ for backwards compatibility. This improves the best practices for working with __annotations__.

Hashes of NaN values of both :class:`float` type and :class:`decimal.Decimal` type now depend on object identity. Formerly, they always hashed to 0 even though NaN values are not equal to one another. This caused potentially quadratic runtime behavior due to excessive hash collisions when creating dictionaries and sets containing multiple NaNs.

A :exc:`SyntaxError` (instead of a :exc:`NameError`) will be raised when deleting the :const:`__debug__` constant.

:exc:`SyntaxError` exceptions now have end_lineno and end_offset attributes. They will be None if not determined.

Add missing :meth:`~asyncio.events.AbstractEventLoop.connect_accepted_socket` method.

The :meth:`~array.array.index` method of :class:`array.array` now has optional start and stop parameters.

Add audit hooks for :func:`gc.get_objects`, :func:`gc.get_referrers` and :func:`gc.get_referents`.

The hashlib module requires OpenSSL 1.1.1 or newer.

The pure-Python fallback of :func:`~hashlib.pbkdf2_hmac` is deprecated. In the future PBKDF2-HMAC will only be available when Python has been built with OpenSSL support.

Add :func:`os.cpu_count()` support for VxWorks RTOS.

Add a new function :func:`os.eventfd` and related helpers to wrap the eventfd2 syscall on Linux.

Add :func:`os.splice()` that allows to move data between two file descriptors without copying between kernel address space and user address space, where one of the file descriptors must refer to a pipe.

Add :data:`~os.O_EVTONLY`, :data:`~os.O_FSYNC`, :data:`~os.O_SYMLINK` and :data:`~os.O_NOFOLLOW_ANY` for macOS.

Add :func:`platform.freedesktop_os_release()` to retrieve operation system identification from The exception :exc:`socket.timeout` is now an alias of :exc:`TimeoutError`.

Add option to create MPTCP sockets with IPPROTO_MPTCP.

Add IP_RECVTOS option to receive the type of service (ToS) or DSCP/ECN fields.

The ssl module requires OpenSSL 1.1.1 or newer.

The ssl module has preliminary support for OpenSSL 3.0.0 and new option :data:`~ssl.OP_IGNORE_UNEXPECTED_EOF`.

Deprecated function and use of deprecated constants now result in a :exc:`DeprecationWarning`. :attr:`ssl.SSLContext.options` has :data:`~ssl.OP_NO_SSLv2` and :data:`~ssl.OP_NO_SSLv3` set by default and therefore cannot warn about setting the flag again.

The ssl module now has more secure default settings. Ciphers without forward secrecy or SHA-1 MAC are disabled by default. Security level 2 prohibits weak RSA, DH, and ECC keys with less than 112 bits of security. :class:`~ssl.SSLContext` defaults to minimum protocol version TLS 1.2. Settings are based on Hynek Schlawack's research.

The deprecated protocols SSL 3.0, TLS 1.0, and TLS 1.1 are no longer officially supported. Python does not block them actively. However OpenSSL build options, distro configurations, vendor patches, and cipher suites may prevent a successful handshake.

Add a timeout parameter to the :func:`ssl.get_server_certificate` function.

The ssl module uses heap-types and multi-phase initialization.

A new verify flag :data:`~ssl.VERIFY_X509_PARTIAL_CHAIN` has been added.

Add :data:`sys.orig_argv` attribute: the list of the original command line arguments passed to the Python executable.

Add :data:`sys.stdlib_module_names`, containing the list of the standard library module names.

:func:`_thread.interrupt_main` now takes an optional signal number to simulate (the default is still :data:`signal.SIGINT`).

[1] (1, 2, 3) The structural pattern matching feature is discussed in /scriptiot/micropython/blob/master/docs/differences/python_310.rst