Python 3.12 正式版整体性能提升了约 5％，带来多项增强

>>> haige = {"name": "haige"}
>>> f"user: { haige["name"] }" 
  File "<stdin>", line 1
    f"user: { haige["name"] }"
                     ^^^^
SyntaxError: f-string: unmatched '['
>>>                            
>>> f'user: { haige["name"] }' 
'user: haige'
>>>
>>> 
>>> 
>>> f"user: { haige['name'] }" 
'user: haige'

>>> songs = ['Take me back to Eden', 'Alkaline', 'Ascensionism']
>>> f"This is the playlist: {", ".join(songs)}"
'This is the playlist: Take me back to Eden, Alkaline, Ascensionism'

>>> f"{'\n'.join(['I', 'love', 'china'])}"
  File "<stdin>", line 1
    f"{'\n'.join(['I', 'love', 'china'])}"
                                          ^
SyntaxError: f-string expression part cannot include a backslash

>>> print(f"This is the playlist: {"\n".join(songs)}")
This is the playlist: Take me back to Eden
Alkaline
Ascensionism
>>> print(f"This is the playlist: {"\N{BLACK HEART SUIT}".join(songs)}")
This is the playlist: Take me back to Eden♥Alkaline♥Ascensionism

s = f"{' '.join([
'I',
'love',
'kobe'
])}"

>>> f"This is the playlist: {", ".join([
...     'Take me back to Eden',  # My, my, those eyes like fire
...     'Alkaline',              # Not acid nor alkaline
...     'Ascensionism'           # Take to the broken skies at last
... ])}"
'This is the playlist: Take me back to Eden, Alkaline, Ascensionism'

>>> def hello():
...     return "Hello World"
...
>>> f"hell() return {":" + hello()}"
'hell() return :Hello World'

>>> f'''A complex trick: {  
... bag['bag'] # recursive bags!  
... }'''  
SyntaxError: f-string expression part cannot include '#'

>>> f"{f"{f"{f"{f"{f"{[i for i in range(10)]}"}"}"}"}"}"
'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]'

Python 3.12.0 (main, Oct  7 2023, 00:19:52) [Clang 14.0.3 (clang-1403.0.22.14.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> sys.version_info
Traceback (most recent call last):
  File "", line 1, in 
NameError: name 'sys' is not defined. Did you forget to import 'sys'?

from typing import TypedDict, Unpack

class Movie(TypedDict):
    name: str
    year: int

def foo(**kwargs: Movie) -> None: ...

movie: dict[str, object] = {"name": "Life of Brian", "year": 1979}
foo(**movie)  # WRONG! Movie is of type dict[str, object]

typed_movie: Movie = {"name": "The Meaning of Life", "year": 1983}
foo(**typed_movie)  # OK!

another_movie = {"name": "Life of Brian", "year": 1979}
foo(**another_movie)  # Depends on the type checker.

from typing import override

class Parent:
    def foo(self) -> int:
        return 1

    def bar(self, x: str) -> str:
        return x

class Child(Parent):
    @override
    def foo(self) -> int:
        return 2

    @override
    def baz() -> int:  # Type check error: no matching signature in ancestor
        return 1

def max[T](args: Iterable[T]) -> T:
    ...

class list[T]:
    def __getitem__(self, index: int, /) -> T:
        ...

    def append(self, element: T) -> None:
        ...

from typing import Generic, TypeVar

_T_co = TypeVar("_T_co", covariant=True, bound=str)

class ClassA(Generic[_T_co]):
    def method1(self) -> _T_co:
        ...

class ClassA[T: str]:
    def method1(self) -> T:
        ...

type ListOrSet[T] = list[T] | set[T]

from typing import TypeAlias

_T = TypeVar("_T")

ListOrSet: TypeAlias = list[_T] | set[_T]