就业培训     下载中心     Wiki     联络
登录   注册
  1. 首页
  2. Python 3.11.0
  3. 索引
  4. 模块
  5. 下一
  6. 上一
  7. Python 的新功能
  8. Python 3.11 有什么新功能

Python 3.11 有什么新功能

发行

3.11.0

日期

2022 年 10 月 24 日

This article explains the new features in Python 3.11, compared to 3.10.

对于完整细节，见 changelog .

摘要 – 发行亮点

  • Python 3.11 is between 10-60% faster than Python 3.10. On average, we measured a 1.25x speedup on the standard benchmark suite. See 更快的 CPython 了解细节。

新句法特征：

新的内置特征：

新标准库模块：

解释器改进：

新类型特征：

Important deprecations, removals and restrictions:

新特征

PEP 657: Fine-grained error locations in tracebacks

When printing tracebacks, the interpreter will now point to the exact expression that caused the error, instead of just the line. For example: 

Traceback (most recent call last):
  File "distance.py", line 11, in <module>
    print(manhattan_distance(p1, p2))
          ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "distance.py", line 6, in manhattan_distance
    return abs(point_1.x - point_2.x) + abs(point_1.y - point_2.y)
                           ^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'x'

Previous versions of the interpreter would point to just the line, making it ambiguous which object was None . These enhanced errors can also be helpful when dealing with deeply nested dict objects and multiple function calls: 

Traceback (most recent call last):
  File "query.py", line 37, in <module>
    magic_arithmetic('foo')
  File "query.py", line 18, in magic_arithmetic
    return add_counts(x) / 25
           ^^^^^^^^^^^^^
  File "query.py", line 24, in add_counts
    return 25 + query_user(user1) + query_user(user2)
                ^^^^^^^^^^^^^^^^^
  File "query.py", line 32, in query_user
    return 1 + query_count(db, response['a']['b']['c']['user'], retry=True)
                               ~~~~~~~~~~~~~~~~~~^^^^^
TypeError: 'NoneType' object is not subscriptable

As well as complex arithmetic expressions: 

Traceback (most recent call last):
  File "calculation.py", line 54, in <module>
    result = (x / y / z) * (a / b / c)
              ~~~~~~^~~
ZeroDivisionError: division by zero

Additionally, the information used by the enhanced traceback feature is made available via a general API, that can be used to correlate bytecode instructions with source code location. This information can be retrieved using:

见 PEP 657 for more details. (Contributed by Pablo Galindo, Batuhan Taskaya and Ammar Askar in bpo-43950 )。

注意

This feature requires storing column positions in 代码对象 , which may result in a small increase in interpreter memory usage and disk usage for compiled Python files. To avoid storing the extra information and deactivate printing the extra traceback information, use the -X no_debug_ranges 命令行选项或 PYTHONNODEBUGRANGES 环境变量。

PEP 654: Exception Groups and except*

PEP 654 introduces language features that enable a program to raise and handle multiple unrelated exceptions simultaneously. The builtin types ExceptionGroup and BaseExceptionGroup make it possible to group exceptions and raise them together, and the new except* syntax generalizes except to match subgroups of exception groups.

见 PEP 654 了解更多细节。

(Contributed by Irit Katriel in bpo-45292 . PEP written by Irit Katriel, Yury Selivanov and Guido van Rossum.)

PEP 678: Exceptions can be enriched with notes

add_note() method is added to BaseException . It can be used to enrich exceptions with context information that is not available at the time when the exception is raised. The added notes appear in the default traceback.

见 PEP 678 了解更多细节。

(Contributed by Irit Katriel in bpo-45607 . PEP written by Zac Hatfield-Dodds.)

Windows py.exe launcher improvements

The copy of the 用于 Windows 的 Python 启动器 included with Python 3.11 has been significantly updated. It now supports company/tag syntax as defined in PEP 514 使用 -V:<company>/<tag> argument instead of the limited -<major>.<minor> . This allows launching distributions other than PythonCore , the one hosted on python.org .

当使用 -V: selectors, either company or tag can be omitted, but all installs will be searched. For example, -V:OtherPython/ will select the “best” tag registered for OtherPython ，而 -V:3.11 or -V:/3.11 will select the “best” distribution with tag 3.11 .

When using the legacy -<major> , -<major>.<minor> , -<major>-<bitness> or -<major>.<minor>-<bitness> arguments, all existing behaviour should be preserved from past versions, and only releases from PythonCore will be selected. However, the -64 suffix now implies “not 32-bit” (not necessarily x86-64), as there are multiple supported 64-bit platforms. 32-bit runtimes are detected by checking the runtime’s tag for a -32 suffix. All releases of Python since 3.5 have included this in their 32-bit builds.

This section covers major changes affecting PEP 484 type hints and the typing 模块。

PEP 646: Variadic generics

PEP 484 previously introduced TypeVar , enabling creation of generics parameterised with a single type. PEP 646 adds TypeVarTuple , enabling parameterisation with an arbitrary number of types. In other words, a TypeVarTuple 是 variadic type variable, enabling variadic generics.

This enables a wide variety of use cases. In particular, it allows the type of array-like structures in numerical computing libraries such as NumPy and TensorFlow to be parameterised with the array shape . Static type checkers will now be able to catch shape-related bugs in code that uses these libraries.

见 PEP 646 了解更多细节。

(Contributed by Matthew Rahtz in bpo-43224 , with contributions by Serhiy Storchaka and Jelle Zijlstra. PEP written by Mark Mendoza, Matthew Rahtz, Pradeep Kumar Srinivasan, and Vincent Siles.)

PEP 655: Marking individual TypedDict items as required or not-required

Required and NotRequired provide a straightforward way to mark whether individual items in a TypedDict must be present. Previously, this was only possible using inheritance.

All fields are still required by default, unless the total parameter is set to False , in which case all fields are still not-required by default. For example, the following specifies a TypedDict with one required and one not-required key: 

class Movie(TypedDict):
   title: str
   year: NotRequired[int]
m1: Movie = {"title": "Black Panther", "year": 2018}  # OK
m2: Movie = {"title": "Star Wars"}  # OK (year is not required)
m3: Movie = {"year": 2022}  # ERROR (missing required field title)

The following definition is equivalent: 

class Movie(TypedDict, total=False):
   title: Required[str]
   year: int

见 PEP 655 了解更多细节。

(Contributed by David Foster and Jelle Zijlstra in bpo-47087 . PEP written by David Foster.)

PEP 673: Self type

新的 Self annotation provides a simple and intuitive way to annotate methods that return an instance of their class. This behaves the same as the TypeVar -based approach specified in PEP 484 , but is more concise and easier to follow.

Common use cases include alternative constructors provided as classmethod s, and __enter__() methods that return self : 

class MyLock:
    def __enter__(self) -> Self:
        self.lock()
        return self
    ...
class MyInt:
    @classmethod
    def fromhex(cls, s: str) -> Self:
        return cls(int(s, 16))
    ...

Self can also be used to annotate method parameters or attributes of the same type as their enclosing class.

见 PEP 673 了解更多细节。

(Contributed by James Hilton-Balfe in bpo-46534 . PEP written by Pradeep Kumar Srinivasan and James Hilton-Balfe.)

PEP 675：任意文字字符串类型

新的 LiteralString annotation may be used to indicate that a function parameter can be of any literal string type. This allows a function to accept arbitrary literal string types, as well as strings created from other literal strings. Type checkers can then enforce that sensitive functions, such as those that execute SQL statements or shell commands, are called only with static arguments, providing protection against injection attacks.

For example, a SQL query function could be annotated as follows: 

def run_query(sql: LiteralString) -> ...
    ...
def caller(
    arbitrary_string: str,
    query_string: LiteralString,
    table_name: LiteralString,
) -> None:
    run_query("SELECT * FROM students")       # ok
    run_query(query_string)                   # ok
    run_query("SELECT * FROM " + table_name)  # ok
    run_query(arbitrary_string)               # type checker error
    run_query(                                # type checker error
        f"SELECT * FROM students WHERE name = {arbitrary_string}"
    )

见 PEP 675 了解更多细节。

(Contributed by Jelle Zijlstra in bpo-47088 . PEP written by Pradeep Kumar Srinivasan and Graham Bleaney.)

PEP 681：数据类变换

dataclass_transform may be used to decorate a class, metaclass, or a function that is itself a decorator. The presence of @dataclass_transform() tells a static type checker that the decorated object performs runtime “magic” that transforms a class, giving it dataclass -like behaviors.

例如： 

# The create_model decorator is defined by a library.
@typing.dataclass_transform()
def create_model(cls: Type[T]) -> Type[T]:
    cls.__init__ = ...
    cls.__eq__ = ...
    cls.__ne__ = ...
    return cls
# The create_model decorator can now be used to create new model classes:
@create_model
class CustomerModel:
    id: int
    name: str
c = CustomerModel(id=327, name="Eric Idle")

见 PEP 681 了解更多细节。

(Contributed by Jelle Zijlstra in gh-91860 . PEP written by Erik De Bonte and Eric Traut.)

PEP 563 may not be the future

PEP 563 Postponed Evaluation of Annotations (the from __future__ import annotations 未来语句 ) that was originally planned for release in Python 3.10 has been put on hold indefinitely. See this message from the Steering Council 了解更多信息。

其它语言变化

  • 添加 -P command line option and a PYTHONSAFEPATH environment variable, which disable the automatic prepending to sys.path of the script’s directory when running a script, or the current directory when using -c and -m . This ensures only stdlib and installed modules are picked up by import , and avoids unintentionally or maliciously shadowing modules with those in a local (and typically user-writable) directory. (Contributed by Victor Stinner in gh-57684 )。

  • "z" option was added to the 格式规范迷你语言 that coerces negative to positive zero after rounding to the format precision. See PEP 682 for more details. (Contributed by John Belmonte in gh-90153 )。

  • Bytes are no longer accepted on sys.path . Support broke sometime between Python 3.2 and 3.6, with no one noticing until after Python 3.10.0 was released. In addition, bringing back support would be problematic due to interactions between -b and sys.path_importer_cache when there is a mixture of str and bytes keys. (Contributed by Thomas Grainger in gh-91181 )。

其它 CPython 实现变化

  • 特殊方法 __complex__() for complex and __bytes__() for bytes are implemented to support the typing.SupportsComplex and typing.SupportsBytes protocols. (Contributed by Mark Dickinson and Dong-hee Na in bpo-24234 )。

  • siphash13 is added as a new internal hashing algorithm. It has similar security properties as siphash24 , but it is slightly faster for long inputs. str , bytes , and some other types now use it as the default algorithm for hash() . PEP 552 hash-based .pyc files now use siphash13 too. (Contributed by Inada Naoki in bpo-29410 )。

  • When an active exception is re-raised by a raise statement with no parameters, the traceback attached to this exception is now always sys.exc_info()[1].__traceback__ . This means that changes made to the traceback in the current except clause are reflected in the re-raised exception. (Contributed by Irit Katriel in bpo-45711 )。

  • The interpreter state’s representation of handled exceptions (aka exc_info or _PyErr_StackItem ) now only has the exc_value field; exc_type and exc_traceback have been removed, as they can be derived from exc_value . (Contributed by Irit Katriel in bpo-45711 )。

  • 新的 command line option , AppendPath , has been added for the Windows installer. It behaves similarly to PrependPath , but appends the install and scripts directories instead of prepending them. (Contributed by Bastian Neuburger in bpo-44934 )。

  • PyConfig.module_search_paths_set field must now be set to 1 for initialization to use PyConfig.module_search_paths to initialize sys.path . Otherwise, initialization will recalculate the path and replace any values added to module_search_paths .

  • The output of the --help option now fits in 50 lines/80 columns. Information about Python environment variables and -X options is now available using the respective --help-env and --help-xoptions flags, and with the new --help-all . (Contributed by Éric Araujo in bpo-46142 )。

  • Converting between int and str in bases other than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10 (decimal) now raises a ValueError if the number of digits in string form is above a limit to avoid potential denial of service attacks due to the algorithmic complexity. This is a mitigation for CVE-2020-10735 . This limit can be configured or disabled by environment variable, command line flag, or sys API。见 整数字符串转换长度局限性 documentation. The default limit is 4300 digits in string form.

新模块

改进模块

asyncio

contextlib

Added non parallel-safe chdir() context manager to change the current working directory and then restore it on exit. Simple wrapper around chdir() . (Contributed by Filipe Laíns in bpo-25625 )

dataclasses

  • Change field default mutability check, allowing only defaults which are hashable instead of any object which is not an instance of dict , list or set . (Contributed by Eric V. Smith in bpo-44674 )。

datetime

enum

fractions

  • 支持 PEP 515 -style initialization of Fraction from string. (Contributed by Sergey B Kirpichev in bpo-44258 )。

  • Fraction now implements an __int__ method, so that an isinstance(some_fraction, typing.SupportsInt) check passes. (Contributed by Mark Dickinson in bpo-44547 )。

functools

  • functools.singledispatch() 现在支持 types.UnionType and typing.Union as annotations to the dispatch argument.: 

    >>> from functools import singledispatch
>>> @singledispatch
... def fun(arg, verbose=False):
...     if verbose:
...         print("Let me just say,", end=" ")
...     print(arg)
...
>>> @fun.register
... def _(arg: int | float, verbose=False):
...     if verbose:
...         print("Strength in numbers, eh?", end=" ")
...     print(arg)
...
>>> from typing import Union
>>> @fun.register
... def _(arg: Union[list, set], verbose=False):
...     if verbose:
...         print("Enumerate this:")
...     for i, elem in enumerate(arg):
...         print(i, elem)
...

    (Contributed by Yurii Karabas in bpo-46014 )。

hashlib

  • hashlib.blake2b() and hashlib.blake2s() now prefer libb2 over Python’s vendored copy. (Contributed by Christian Heimes in bpo-47095 )。

  • The internal _sha3 module with SHA3 and SHAKE algorithms now uses tiny_sha3 而不是 Keccak Code Package to reduce code and binary size. The hashlib module prefers optimized SHA3 and SHAKE implementations from OpenSSL. The change affects only installations without OpenSSL support. (Contributed by Christian Heimes in bpo-47098 )。

  • 添加 hashlib.file_digest() , a helper function for efficient hashing of files or file-like objects. (Contributed by Christian Heimes in gh-89313 )。

IDLE and idlelib

  • Apply syntax highlighting to .pyi files. (Contributed by Alex Waygood and Terry Jan Reedy in bpo-45447 )。

  • Include prompts when saving Shell with inputs and outputs. (Contributed by Terry Jan Reedy in gh-95191 )。

inspect

locale

logging

math

  • 添加 math.exp2() : return 2 raised to the power of x. (Contributed by Gideon Mitchell in bpo-45917 )。

  • 添加 math.cbrt() : return the cube root of x. (Contributed by Ajith Ramachandran in bpo-44357 )。

  • The behaviour of two math.pow() corner cases was changed, for consistency with the IEEE 754 specification. The operations math.pow(0.0, -math.inf) and math.pow(-0.0, -math.inf) 现在返回 inf . Previously they raised ValueError . (Contributed by Mark Dickinson in bpo-44339 )。

  • math.nan value is now always available. (Contributed by Victor Stinner in bpo-46917 )。

operator

  • A new function operator.call has been added, such that operator.call(obj, *args, **kwargs) == obj(*args, **kwargs) . (Contributed by Antony Lee in bpo-44019 )。

os

  • 在 Windows， os.urandom() 现在使用 BCryptGenRandom() ，而不是 CryptGenRandom() which is deprecated. (Contributed by Dong-hee Na in bpo-44611 )。

pathlib

re

  • Atomic grouping ( (?>...) ) and possessive quantifiers ( *+ , ++ , ?+ , {m,n}+ ) are now supported in regular expressions. (Contributed by Jeffrey C. Jacobs and Serhiy Storchaka in bpo-433030 )。

shutil

socket

sqlite3

string

sys

  • sys.exc_info() now derives the type and traceback 字段来自 value (the exception instance), so when an exception is modified while it is being handled, the changes are reflected in the results of subsequent calls to exc_info() . (Contributed by Irit Katriel in bpo-45711 )。

  • 添加 sys.exception() which returns the active exception instance (equivalent to sys.exc_info()[1] ). (Contributed by Irit Katriel in bpo-46328 )。

  • 添加 sys.flags.safe_path flag. (Contributed by Victor Stinner in gh-57684 )。

sysconfig

  • Three new installation schemes ( posix_venv , nt_venv and venv ) were added and are used when Python creates new virtual environments or when it is running from a virtual environment. The first two schemes ( posix_venv and nt_venv ) are OS-specific for non-Windows and Windows, the venv is essentially an alias to one of them according to the OS Python runs on. This is useful for downstream distributors who modify sysconfig.get_preferred_scheme() . Third party code that creates new virtual environments should use the new venv installation scheme to determine the paths, as does venv . (Contributed by Miro Hrončok in bpo-45413 )。

threading

time

  • 在 Unix， time.sleep() now uses the clock_nanosleep() or nanosleep() function, if available, which has a resolution of 1 nanosecond (10 -9 seconds), rather than using select() which has a resolution of 1 microsecond (10 -6 seconds). (Contributed by Benjamin Szőke and Victor Stinner in bpo-21302 )。

  • On Windows 8.1 and newer, time.sleep() now uses a waitable timer based on high-resolution timers which has a resolution of 100 nanoseconds (10 -7 seconds). Previously, it had a resolution of 1 millisecond (10 -3 seconds). (Contributed by Benjamin Szőke, Dong-hee Na, Eryk Sun and Victor Stinner in bpo-21302 and bpo-45429 )。

traceback

typing

For major changes, see New Features Related to Type Hints .

tkinter

  • Added method info_patchlevel() which returns the exact version of the Tcl library as a named tuple similar to sys.version_info . (Contributed by Serhiy Storchaka in gh-91827 )。

unicodedata

  • The Unicode database has been updated to version 14.0.0. (Contributed by Benjamin Peterson in bpo-45190 ).

unittest

venv

  • When new Python virtual environments are created, the venv sysconfig installation scheme is used to determine the paths inside the environment. When Python runs in a virtual environment, the same installation scheme is the default. That means that downstream distributors can change the default sysconfig install scheme without changing behavior of virtual environments. Third party code that also creates new virtual environments should do the same. (Contributed by Miro Hrončok in bpo-45413 )。

warnings

zipfile

fcntl

  • On FreeBSD, the F_DUP2FD and F_DUP2FD_CLOEXEC flags respectively are supported, the former equals to dup2 usage while the latter set the FD_CLOEXEC flag in addition.

优化

This section covers specific optimizations independent of the 更快的 CPython project, which is covered in its own section.

  • The compiler now optimizes simple printf-style % formatting on string literals containing only the format codes %s , %r and %a and makes it as fast as a corresponding f-string expression. (Contributed by Serhiy Storchaka in bpo-28307 )。

  • Integer division ( // ) is better tuned for optimization by compilers. It is now around 20% faster on x86-64 when dividing an int by a value smaller than 2**30 . (Contributed by Gregory P. Smith and Tim Peters in gh-90564 )。

  • sum() is now nearly 30% faster for integers smaller than 2**30 . (Contributed by Stefan Behnel in gh-68264 )。

  • Resizing lists is streamlined for the common case, speeding up list.append() by ≈15% and simple 列表推导 s by up to 20-30% (Contributed by Dennis Sweeney in gh-91165 )。

  • Dictionaries don’t store hash values when all keys are Unicode objects, decreasing dict size. For example, sys.getsizeof(dict.fromkeys("abcdefg")) is reduced from 352 bytes to 272 bytes (23% smaller) on 64-bit platforms. (Contributed by Inada Naoki in bpo-46845 )。

  • 使用 asyncio.DatagramProtocol is now orders of magnitude faster when transferring large files over UDP, with speeds over 100 times higher for a ≈60 MiB file. (Contributed by msoxzw in gh-91487 )。

  • math 函数 comb() and perm() are now ≈10 times faster for large arguments (with a larger speedup for larger k ). (Contributed by Serhiy Storchaka in bpo-37295 )。

  • statistics 函数 mean() , variance() and stdev() now consume iterators in one pass rather than converting them to a list first. This is twice as fast and can save substantial memory. (Contributed by Raymond Hettinger in gh-90415 )。

  • unicodedata.normalize() now normalizes pure-ASCII strings in constant time. (Contributed by Dong-hee Na in bpo-44987 )。

更快的 CPython

CPython 3.11 is on average 25% faster than CPython 3.10 when measured with the pyperformance benchmark suite, and compiled with GCC on Ubuntu Linux. Depending on your workload, the speedup could be up to 10-60% faster.

This project focuses on two major areas in Python: faster startup and faster runtime. Other optimizations not under this project are listed in 优化 .

Faster Startup

Frozen imports / Static code objects

Python caches bytecode in the __pycache__ directory to speed up module loading.

Previously in 3.10, Python module execution looked like this: 

Read __pycache__ -> Unmarshal -> Heap allocated code object -> Evaluate

In Python 3.11, the core modules essential for Python startup are “frozen”. This means that their code objects (and bytecode) are statically allocated by the interpreter. This reduces the steps in module execution process to this: 

Statically allocated code object -> Evaluate

Interpreter startup is now 10-15% faster in Python 3.11. This has a big impact for short-running programs using Python.

(Contributed by Eric Snow, Guido van Rossum and Kumar Aditya in numerous issues.)

Faster Runtime

Cheaper, lazy Python frames

Python frames are created whenever Python calls a Python function. This frame holds execution information. The following are new frame optimizations:

  • Streamlined the frame creation process.

  • Avoided memory allocation by generously re-using frame space on the C stack.

  • Streamlined the internal frame struct to contain only essential information. Frames previously held extra debugging and memory management information.

Old-style frame objects are now created only when requested by debuggers or by Python introspection functions such as sys._getframe or inspect.currentframe . For most user code, no frame objects are created at all. As a result, nearly all Python functions calls have sped up significantly. We measured a 3-7% speedup in pyperformance.

(Contributed by Mark Shannon in bpo-44590 )。

Inlined Python function calls

During a Python function call, Python will call an evaluating C function to interpret that function’s code. This effectively limits pure Python recursion to what’s safe for the C stack.

In 3.11, when CPython detects Python code calling another Python function, it sets up a new frame, and “jumps” to the new code inside the new frame. This avoids calling the C interpreting function altogether.

Most Python function calls now consume no C stack space. This speeds up most of such calls. In simple recursive functions like fibonacci or factorial, a 1.7x speedup was observed. This also means recursive functions can recurse significantly deeper (if the user increases the recursion limit). We measured a 1-3% improvement in pyperformance.

(Contributed by Pablo Galindo and Mark Shannon in bpo-45256 )。

PEP 659: Specializing Adaptive Interpreter

PEP 659 is one of the key parts of the faster CPython project. The general idea is that while Python is a dynamic language, most code has regions where objects and types rarely change. This concept is known as type stability .

At runtime, Python will try to look for common patterns and type stability in the executing code. Python will then replace the current operation with a more specialized one. This specialized operation uses fast paths available only to those use cases/types, which generally outperform their generic counterparts. This also brings in another concept called inline caching , where Python caches the results of expensive operations directly in the bytecode.

The specializer will also combine certain common instruction pairs into one superinstruction. This reduces the overhead during execution.

Python will only specialize when it sees code that is “hot” (executed multiple times). This prevents Python from wasting time for run-once code. Python can also de-specialize when code is too dynamic or when the use changes. Specialization is attempted periodically, and specialization attempts are not too expensive. This allows specialization to adapt to new circumstances.

(PEP written by Mark Shannon, with ideas inspired by Stefan Brunthaler. See PEP 659 for more information. Implementation by Mark Shannon and Brandt Bucher, with additional help from Irit Katriel and Dennis Sweeney.)

操作 表单 Specialization Operation speedup (up to) Contributor(s)
Binary operations x+x; x*x; x-x; Binary add, multiply and subtract for common types such as int , float ，和 str take custom fast paths for their underlying types. 10% Mark Shannon, Dong-hee Na, Brandt Bucher, Dennis Sweeney
Subscript a[i] Subscripting container types such as list , tuple and dict directly index the underlying data structures.

Subscripting custom __getitem__ is also inlined similar to Inlined Python function calls .

10-25% Irit Katriel, Mark Shannon
Store subscript a[i] = z Similar to subscripting specialization above. 10-25% Dennis Sweeney
调用 f(arg) C(arg) Calls to common builtin (C) functions and types such as len and str directly call their underlying C version. This avoids going through the internal calling convention. 20% Mark Shannon, Ken Jin
Load global variable print len The object’s index in the globals/builtins namespace is cached. Loading globals and builtins require zero namespace lookups. 1 Mark Shannon
Load attribute o.attr Similar to loading global variables. The attribute’s index inside the class/object’s namespace is cached. In most cases, attribute loading will require zero namespace lookups. 2 Mark Shannon
Load methods for call o.meth() The actual address of the method is cached. Method loading now has no namespace lookups – even for classes with long inheritance chains. 10-20% Ken Jin, Mark Shannon
Store attribute o.attr = z Similar to load attribute optimization. 2% in pyperformance Mark Shannon
Unpack Sequence *seq Specialized for common containers such as list and tuple . Avoids internal calling convention. 8% Brandt Bucher
1

A similar optimization already existed since Python 3.8. 3.11 specializes for more forms and reduces some overhead.

2

A similar optimization already existed since Python 3.10. 3.11 specializes for more forms. Furthermore, all attribute loads should be sped up by bpo-45947 .

Misc

  • Objects now require less memory due to lazily created object namespaces. Their namespace dictionaries now also share keys more freely. (Contributed Mark Shannon in bpo-45340 and bpo-40116 )。

  • A more concise representation of exceptions in the interpreter reduced the time required for catching an exception by about 10%. (Contributed by Irit Katriel in bpo-45711 )。

FAQ

Q: How should I write my code to utilize these speedups?
A: You don’t have to change your code. Write Pythonic code that follows common best practices. The Faster CPython project optimizes for common code patterns we observe.
Q: Will CPython 3.11 use more memory?
A: Maybe not. We don’t expect memory use to exceed 20% more than 3.10. This is offset by memory optimizations for frame objects and object dictionaries as mentioned above.
Q: I don’t see any speedups in my workload. Why?
A: Certain code won’t have noticeable benefits. If your code spends most of its time on I/O operations, or already does most of its computation in a C extension library like numpy, there won’t be significant speedup. This project currently benefits pure-Python workloads the most.
Furthermore, the pyperformance figures are a geometric mean. Even within the pyperformance benchmarks, certain benchmarks have slowed down slightly, while others have sped up by nearly 2x!
Q: Is there a JIT compiler?
A: No. We’re still exploring other optimizations.

关于

Faster CPython explores optimizations for CPython . The main team is funded by Microsoft to work on this full-time. Pablo Galindo Salgado is also funded by Bloomberg LP to work on the project part-time. Finally, many contributors are volunteers from the community.

CPython 字节码变化

弃用

This section lists Python APIs that have been deprecated in Python 3.11.

Deprecated C APIs are listed separately .

  • PEP 594 led to the deprecations of the following modules which are slated for removal in Python 3.13:

    (Contributed by Brett Cannon in bpo-47061 and Victor Stinner in gh-68966 )。

  • asynchat , asyncore and smtpd modules have been deprecated since at least Python 3.6. Their documentation and deprecation warnings have now been updated to note they will removed in Python 3.12. (Contributed by Hugo van Kemenade in bpo-47022 )。

  • More strict rules will be applied now applied for numerical group references and group names in regular expressions in future Python versions. Only sequence of ASCII digits will be now accepted as a numerical reference. The group name in bytes patterns and replacement strings could only contain ASCII letters and digits and underscore. For now, a deprecation warning is raised for such syntax. (Contributed by Serhiy Storchaka in gh-91760 )。

  • typing.Text , which exists solely to provide compatibility support between Python 2 and Python 3 code, is now deprecated. Its removal is currently unplanned, but users are encouraged to use str instead wherever possible. (Contributed by Alex Waygood in gh-92332 )。

  • The keyword argument syntax for constructing TypedDict types is now deprecated. Support will be removed in Python 3.13. (Contributed by Jingchen Ye in gh-90224 )。

  • re.template() function and the corresponding re.TEMPLATE and re.T flags are deprecated, as they were undocumented and lacked an obvious purpose. They will be removed in Python 3.13. (Contributed by Serhiy Storchaka and Miro Hrončok in gh-92728 )。

Pending Removal in Python 3.12

The following Python APIs have been deprecated in earlier Python releases, and will be removed in Python 3.12.

C APIs pending removal are listed separately .

移除

This section lists Python APIs that have been removed in Python 3.12.

Removed C APIs are listed separately .

  • 移除 @asyncio.coroutine() 装饰器 enabling legacy generator-based coroutines to be compatible with async / await code. The function has been deprecated since Python 3.8 and the removal was initially scheduled for Python 3.10. Use async def instead. (Contributed by Illia Volochii in bpo-43216 )。

  • 移除 asyncio.coroutines.CoroWrapper used for wrapping legacy generator-based coroutine objects in the debug mode. (Contributed by Illia Volochii in bpo-43216 )。

  • Due to significant security concerns, the reuse_address 参数对于 asyncio.loop.create_datagram_endpoint() , disabled in Python 3.9, is now entirely removed. This is because of the behavior of the socket option SO_REUSEADDR in UDP. (Contributed by Hugo van Kemenade in bpo-45129 )。

  • 移除 binhex module, deprecated in Python 3.9. Also removed the related, similarly-deprecated binascii functions:

    • binascii.a2b_hqx()

    • binascii.b2a_hqx()

    • binascii.rlecode_hqx()

    • binascii.rldecode_hqx()

    binascii.crc_hqx() function remains available.

    (Contributed by Victor Stinner in bpo-45085 )。

  • 移除 distutils bdist_msi command deprecated in Python 3.9. Use bdist_wheel (wheel packages) instead. (Contributed by Hugo van Kemenade in bpo-45124 )。

  • 移除 __getitem__() methods of xml.dom.pulldom.DOMEventStream , wsgiref.util.FileWrapper and fileinput.FileInput , deprecated since Python 3.9. (Contributed by Hugo van Kemenade in bpo-45132 )。

  • Removed the deprecated gettext 函数 lgettext() , ldgettext() , lngettext() and ldngettext() . Also removed the bind_textdomain_codeset() 函数， NullTranslations.output_charset() and NullTranslations.set_output_charset() methods, and the codeset 参数对于 translation() and install() , since they are only used for the l*gettext() functions. (Contributed by Dong-hee Na and Serhiy Storchaka in bpo-44235 )。

  • Removed from the inspect 模块：

    (Contributed by Hugo van Kemenade in bpo-45320 )。

  • 移除 __class_getitem__() method from pathlib.PurePath , because it was not used and added by mistake in previous versions. (Contributed by Nikita Sobolev in bpo-46483 )。

  • 移除 MailmanProxy 类在 smtpd module, as it is unusable without the external mailman package. (Contributed by Dong-hee Na in bpo-35800 )。

  • Removed the deprecated split() 方法为 _tkinter.TkappType . (Contributed by Erlend E. Aasland in bpo-38371 )。

  • Removed namespace package support from unittest discovery. It was introduced in Python 3.4 but has been broken since Python 3.7. (Contributed by Inada Naoki in bpo-23882 )。

  • Removed the undocumented private float.__set_format__() method, previously known as float.__setformat__() in Python 3.7. Its docstring said: “You probably don’t want to use this function. It exists mainly to be used in Python’s test suite.” (Contributed by Victor Stinner in bpo-46852 )。

  • --experimental-isolated-subinterpreters configure flag (and corresponding EXPERIMENTAL_ISOLATED_SUBINTERPRETERS macro) have been removed.

  • Pynche — The Pythonically Natural Color and Hue Editor — has been moved out of Tools/scripts and is being developed independently from the Python source tree.

移植到 Python 3.11

This section lists previously described changes and other bugfixes in the Python API that may require changes to your Python code.

Porting notes for the C API are listed separately .

构建变化

  • CPython now has PEP 11 Tier 3 support for cross compiling to the WebAssembly 平台 Emscripten ( wasm32-unknown-emscripten , i.e. Python in the browser) and WebAssembly System Interface (WASI) ( wasm32-unknown-wasi ). The effort is inspired by previous work like Pyodide . These platforms provide a limited subset of POSIX APIs; Python standard libraries features and modules related to networking, processes, threading, signals, mmap, and users/groups are not available or don’t work. (Emscripten contributed by Christian Heimes and Ethan Smith in gh-84461 and WASI contributed by Christian Heimes in gh-90473 ; platforms promoted in gh-95085 )

  • Building Python now requires:

  • tkinter package now requires Tcl/Tk version 8.5.12 or newer. (Contributed by Serhiy Storchaka in bpo-46996 )。

  • Build dependencies, compiler flags, and linker flags for most stdlib extension modules are now detected by configure . libffi, libnsl, libsqlite3, zlib, bzip2, liblzma, libcrypt, Tcl/Tk, and uuid flags are detected by pkg-config (when available). tkinter now requires a pkg-config command to detect development settings for Tcl/Tk headers and libraries. (Contributed by Christian Heimes and Erlend Egeberg Aasland in bpo-45847 , bpo-45747 ，和 bpo-45763 )。

  • libpython is no longer linked against libcrypt. (Contributed by Mike Gilbert in bpo-45433 )。

  • CPython can now be built with the ThinLTO option via passing thin to --with-lto , i.e. --with-lto=thin . (Contributed by Dong-hee Na and Brett Holman in bpo-44340 )。

  • Freelists for object structs can now be disabled. A new configure option --without-freelists can be used to disable all freelists except empty tuple singleton. (Contributed by Christian Heimes in bpo-45522 )。

  • Modules/Setup and Modules/makesetup have been improved and tied up. Extension modules can now be built through makesetup . All except some test modules can be linked statically into a main binary or library. (Contributed by Brett Cannon and Christian Heimes in bpo-45548 , bpo-45570 , bpo-45571 ，和 bpo-43974 )。

    注意

    Use the environment variables TCLTK_CFLAGS and TCLTK_LIBS to manually specify the location of Tcl/Tk headers and libraries. The configure 选项 --with-tcltk-includes and --with-tcltk-libs have been removed.

    On RHEL 7 and CentOS 7 the development packages do not provide tcl.pc and tk.pc ；使用 TCLTK_LIBS="-ltk8.5 -ltkstub8.5 -ltcl8.5" . The directory Misc/rhel7 包含 .pc files and instructions on how to build Python with RHEL 7’s and CentOS 7’s Tcl/Tk and OpenSSL.

  • CPython will now use 30-bit digits by default for the Python int implementation. Previously, the default was to use 30-bit digits on platforms with SIZEOF_VOID_P >= 8 , and 15-bit digits otherwise. It’s still possible to explicitly request use of 15-bit digits via either the --enable-big-digits option to the configure script or (for Windows) the PYLONG_BITS_IN_DIGIT variable in PC/pyconfig.h , but this option may be removed at some point in the future. (Contributed by Mark Dickinson in bpo-45569 )。

C API 变化

新特征

移植到 Python 3.11

  • Some macros have been converted to static inline functions to avoid macro pitfalls . The change should be mostly transparent to users, as the replacement functions will cast their arguments to the expected types to avoid compiler warnings due to static type checks. However, when the limited C API is set to >=3.11, these casts are not done, and callers will need to cast arguments to their expected types. See PEP 670 for more details. (Contributed by Victor Stinner and Erlend E. Aasland in gh-89653 )。

  • PyErr_SetExcInfo() no longer uses the type and traceback arguments, the interpreter now derives those values from the exception instance (the value argument). The function still steals references of all three arguments. (Contributed by Irit Katriel in bpo-45711 )。

  • PyErr_GetExcInfo() now derives the type and traceback fields of the result from the exception instance (the value field). (Contributed by Irit Katriel in bpo-45711 )。

  • _frozen 拥有新的 is_package field to indicate whether or not the frozen module is a package. Previously, a negative value in the size field was the indicator. Now only non-negative values be used for size . (Contributed by Kumar Aditya in bpo-46608 )。

  • _PyFrameEvalFunction() now takes _PyInterpreterFrame* as its second parameter, instead of PyFrameObject* 。见 PEP 523 for more details of how to use this function pointer type.

  • PyCode_New() and PyCode_NewWithPosOnlyArgs() now take an additional exception_table argument. Using these functions should be avoided, if at all possible. To get a custom code object: create a code object using the compiler, then get a modified version with the replace 方法。

  • PyCodeObject no longer has the co_code , co_varnames , co_cellvars and co_freevars fields. Instead, use PyCode_GetCode() , PyCode_GetVarnames() , PyCode_GetCellvars() and PyCode_GetFreevars() respectively to access them via the C API. (Contributed by Brandt Bucher in bpo-46841 and Ken Jin in gh-92154 and gh-94936 )。

  • The old trashcan macros ( Py_TRASHCAN_SAFE_BEGIN / Py_TRASHCAN_SAFE_END ) are now deprecated. They should be replaced by the new macros Py_TRASHCAN_BEGIN and Py_TRASHCAN_END .

    A tp_dealloc function that has the old macros, such as: 

    static void
mytype_dealloc(mytype *p)
{
    PyObject_GC_UnTrack(p);
    Py_TRASHCAN_SAFE_BEGIN(p);
    ...
    Py_TRASHCAN_SAFE_END
}

    should migrate to the new macros as follows: 

    static void
mytype_dealloc(mytype *p)
{
    PyObject_GC_UnTrack(p);
    Py_TRASHCAN_BEGIN(p, mytype_dealloc)
    ...
    Py_TRASHCAN_END
}

    注意， Py_TRASHCAN_BEGIN has a second argument which should be the deallocation function it is in.

    To support older Python versions in the same codebase, you can define the following macros and use them throughout the code (credit: these were copied from the mypy codebase): 

    #if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 8
#  define CPy_TRASHCAN_BEGIN(op, dealloc) Py_TRASHCAN_BEGIN(op, dealloc)
#  define CPy_TRASHCAN_END(op) Py_TRASHCAN_END
#else
#  define CPy_TRASHCAN_BEGIN(op, dealloc) Py_TRASHCAN_SAFE_BEGIN(op)
#  define CPy_TRASHCAN_END(op) Py_TRASHCAN_SAFE_END(op)
#endif

  • PyType_Ready() function now raises an error if a type is defined with the Py_TPFLAGS_HAVE_GC flag set but has no traverse function ( PyTypeObject.tp_traverse ). (Contributed by Victor Stinner in bpo-44263 )。

  • Heap types with the Py_TPFLAGS_IMMUTABLETYPE flag can now inherit the PEP 590 vectorcall protocol. Previously, this was only possible for static types . (Contributed by Erlend E. Aasland in bpo-43908 )

  • 由于 Py_TYPE() is changed to a inline static function, Py_TYPE(obj) = new_type must be replaced with Py_SET_TYPE(obj, new_type) ：见 Py_SET_TYPE() function (available since Python 3.9). For backward compatibility, this macro can be used: 

    #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_TYPE)
static inline void _Py_SET_TYPE(PyObject *ob, PyTypeObject *type)
{ ob->ob_type = type; }
#define Py_SET_TYPE(ob, type) _Py_SET_TYPE((PyObject*)(ob), type)
#endif

    (Contributed by Victor Stinner in bpo-39573 )。

  • 由于 Py_SIZE() is changed to a inline static function, Py_SIZE(obj) = new_size must be replaced with Py_SET_SIZE(obj, new_size) ：见 Py_SET_SIZE() function (available since Python 3.9). For backward compatibility, this macro can be used: 

    #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_SIZE)
static inline void _Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size)
{ ob->ob_size = size; }
#define Py_SET_SIZE(ob, size) _Py_SET_SIZE((PyVarObject*)(ob), size)
#endif

    (Contributed by Victor Stinner in bpo-39573 )。

  • <Python.h> no longer includes the header files <stdlib.h> , <stdio.h> , <errno.h> and <string.h> 当 Py_LIMITED_API macro is set to 0x030b0000 (Python 3.11) or higher. C extensions should explicitly include the header files after #include <Python.h> . (Contributed by Victor Stinner in bpo-45434 )。

  • The non-limited API files cellobject.h , classobject.h , code.h , context.h , funcobject.h , genobject.h and longintrepr.h have been moved to the Include/cpython directory. Moreover, the eval.h header file was removed. These files must not be included directly, as they are already included in Python.h : 包括文件 . If they have been included directly, consider including Python.h instead. (Contributed by Victor Stinner in bpo-35134 )。

  • PyUnicode_CHECK_INTERNED() macro has been excluded from the limited C API. It was never usable there, because it used internal structures which are not available in the limited C API. (Contributed by Victor Stinner in bpo-46007 )。

  • The following frame functions and type are now directly available with #include <Python.h> , it’s no longer needed to add #include <frameobject.h> :

    (Contributed by Victor Stinner in gh-93937 )。

  • PyFrameObject structure members have been removed from the public C API.

    While the documentation notes that the PyFrameObject fields are subject to change at any time, they have been stable for a long time and were used in several popular extensions.

    In Python 3.11, the frame struct was reorganized to allow performance optimizations. Some fields were removed entirely, as they were details of the old implementation.

    PyFrameObject 字段：

    The Python frame object is now created lazily. A side effect is that the f_back member must not be accessed directly, since its value is now also computed lazily. The PyFrame_GetBack() function must be called instead.

    Debuggers that accessed the f_locals directly must call PyFrame_GetLocals() instead. They no longer need to call PyFrame_FastToLocalsWithError() or PyFrame_LocalsToFast() , in fact they should not call those functions. The necessary updating of the frame is now managed by the virtual machine.

    Code defining PyFrame_GetCode() on Python 3.8 and older: 

    #if PY_VERSION_HEX < 0x030900B1
static inline PyCodeObject* PyFrame_GetCode(PyFrameObject *frame)
{
    Py_INCREF(frame->f_code);
    return frame->f_code;
}
#endif

    Code defining PyFrame_GetBack() on Python 3.8 and older: 

    #if PY_VERSION_HEX < 0x030900B1
static inline PyFrameObject* PyFrame_GetBack(PyFrameObject *frame)
{
    Py_XINCREF(frame->f_back);
    return frame->f_back;
}
#endif

    Or use the pythoncapi_compat project to get these two functions on older Python versions.

  • Changes of the PyThreadState structure members:

    Code defining PyThreadState_GetFrame() on Python 3.8 and older: 

    #if PY_VERSION_HEX < 0x030900B1
static inline PyFrameObject* PyThreadState_GetFrame(PyThreadState *tstate)
{
    Py_XINCREF(tstate->frame);
    return tstate->frame;
}
#endif

    Code defining PyThreadState_EnterTracing() and PyThreadState_LeaveTracing() on Python 3.10 and older: 

    #if PY_VERSION_HEX < 0x030B00A2
static inline void PyThreadState_EnterTracing(PyThreadState *tstate)
{
    tstate->tracing++;
#if PY_VERSION_HEX >= 0x030A00A1
    tstate->cframe->use_tracing = 0;
#else
    tstate->use_tracing = 0;
#endif
}
static inline void PyThreadState_LeaveTracing(PyThreadState *tstate)
{
    int use_tracing = (tstate->c_tracefunc != NULL || tstate->c_profilefunc != NULL);
    tstate->tracing--;
#if PY_VERSION_HEX >= 0x030A00A1
    tstate->cframe->use_tracing = use_tracing;
#else
    tstate->use_tracing = use_tracing;
#endif
}
#endif

    或使用 the pythoncapi_compat project to get these functions on old Python functions.

  • Distributors are encouraged to build Python with the optimized Blake2 library libb2 .

  • PyConfig.module_search_paths_set field must now be set to 1 for initialization to use PyConfig.module_search_paths to initialize sys.path . Otherwise, initialization will recalculate the path and replace any values added to module_search_paths .

  • PyConfig_Read() no longer calculates the initial search path, and will not fill any values into PyConfig.module_search_paths . To calculate default paths and then modify them, finish initialization and use PySys_GetObject() to retrieve sys.path as a Python list object and modify it directly.

弃用

Pending Removal in Python 3.12

The following C APIs have been deprecated in earlier Python releases, and will be removed in Python 3.12.

移除

  • PyFrame_BlockSetup() and PyFrame_BlockPop() have been removed. (Contributed by Mark Shannon in bpo-40222 )。

  • Remove the following math macros using the errno 变量：

    • Py_ADJUST_ERANGE1()

    • Py_ADJUST_ERANGE2()

    • Py_OVERFLOWED()

    • Py_SET_ERANGE_IF_OVERFLOW()

    • Py_SET_ERRNO_ON_MATH_ERROR()

    (Contributed by Victor Stinner in bpo-45412 )。

  • 移除 Py_UNICODE_COPY() and Py_UNICODE_FILL() macros, deprecated since Python 3.3. Use PyUnicode_CopyCharacters() or memcpy() ( wchar_t* string), and PyUnicode_Fill() functions instead. (Contributed by Victor Stinner in bpo-41123 )。

  • Remove the pystrhex.h header file. It only contains private functions. C extensions should only include the main <Python.h> header file. (Contributed by Victor Stinner in bpo-45434 )。

  • Remove the Py_FORCE_DOUBLE() macro. It was used by the Py_IS_INFINITY() macro. (Contributed by Victor Stinner in bpo-45440 )。

  • The following items are no longer available when Py_LIMITED_API is defined:

    These are not part of the limited API .

    (Contributed by Victor Stinner in bpo-45474 )。

  • Exclude PyWeakref_GET_OBJECT() from the limited C API. It never worked since the PyWeakReference structure is opaque in the limited C API. (Contributed by Victor Stinner in bpo-35134 )。

  • Remove the PyHeapType_GET_MEMBERS() macro. It was exposed in the public C API by mistake, it must only be used by Python internally. Use the PyTypeObject.tp_members member instead. (Contributed by Victor Stinner in bpo-40170 )。

  • Remove the HAVE_PY_SET_53BIT_PRECISION macro (moved to the internal C API). (Contributed by Victor Stinner in bpo-45412 )。

  • Remove the Py_UNICODE encoder APIs, as they have been deprecated since Python 3.3, are little used and are inefficient relative to the recommended alternatives.

    The removed functions are:

    • PyUnicode_Encode()

    • PyUnicode_EncodeASCII()

    • PyUnicode_EncodeLatin1()

    • PyUnicode_EncodeUTF7()

    • PyUnicode_EncodeUTF8()

    • PyUnicode_EncodeUTF16()

    • PyUnicode_EncodeUTF32()

    • PyUnicode_EncodeUnicodeEscape()

    • PyUnicode_EncodeRawUnicodeEscape()

    • PyUnicode_EncodeCharmap()

    • PyUnicode_TranslateCharmap()

    • PyUnicode_EncodeDecimal()

    • PyUnicode_TransformDecimalToASCII()

    见 PEP 624 for details and migration guidance . (Contributed by Inada Naoki in bpo-44029 )。

内容表

上一话题

Python 的新功能

下一话题

What’s New In Python 3.10

本页

  1. 首页
  2. Python 3.11.0
  3. 索引
  4. 模块
  5. 下一
  6. 上一
  7. Python 的新功能
  8. Python 3.11 有什么新功能