Editors: | Elvis Pranskevichus < elvis @ magic . io >, Yury Selivanov < yury @ magic . io > |
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This article explains the new features in Python 3.6, compared to 3.5. Python 3.6 was released on December 23, 2016. For full details, see the changelog .
另请参阅
PEP 494 - Python 3.6 发行时间表
新句法特征:
New library modules:
CPython 实现改善:
**kwargs
now
corresponds to the order
in which keyword
arguments were passed to the function.
Significant improvements in the standard library:
asyncio
module has received new features, significant
usability and performance improvements, and a fair amount of bug fixes.
Starting with Python 3.6 the
asyncio
module is no longer provisional
and its API is considered stable.
datetime
module has gained support for
Local Time Disambiguation
.
typing
module received a number of
improvements
.
tracemalloc
module has been significantly reworked
and is now used to provide better output for
ResourceWarning
as well as provide better diagnostics for memory allocation errors.
见
PYTHONMALLOC section
for more
information.
Security improvements:
secrets
module has been added to simplify the generation of
cryptographically strong pseudo-random numbers suitable for
managing secrets such as account authentication, tokens, and similar.
os.urandom()
now blocks until the system urandom entropy
pool is initialized to increase the security. See the
PEP 524
为
rationale.
hashlib
and
ssl
modules now support OpenSSL 1.1.0.
ssl
module have been
improved.
hashlib
module received support for the BLAKE2, SHA-3 and SHAKE
hash algorithms and the
scrypt()
key derivation function.
Windows improvements:
py.exe
launcher, when used interactively, no longer prefers
Python 2 over Python 3 when the user doesn’t specify a version (via
command line arguments or a config file). Handling of shebang lines
remains unchanged - “python” refers to Python 2 in that case.
python.exe
and
pythonw.exe
have been marked as long-path aware,
which means that the 260 character path limit may no longer apply.
见
removing the MAX_PATH limitation
了解细节。
._pth
file can be added to force isolated mode and fully specify
all search paths to avoid registry and environment lookup. See
the documentation
了解更多信息。
python36.zip
file now works as a landmark to infer
PYTHONHOME
。见
the documentation
for
more information.
PEP 498 引入一种新的字符串文字: f-strings ,或 格式化字符串文字 .
Formatted string literals are prefixed with
'f'
and are similar to the format strings accepted by
str.format()
. They contain replacement fields surrounded by curly braces. The replacement fields are expressions, which are evaluated at run time, and then formatted using the
format()
协议:
>>> name = "Fred"
>>> f"He said his name is {name}."
'He said his name is Fred.'
>>> width = 10
>>> precision = 4
>>> value = decimal.Decimal("12.34567")
>>> f"result: {value:{width}.{precision}}" # nested fields
'result: 12.35'
PEP 484 introduced the standard for type annotations of function parameters, a.k.a. type hints. This PEP adds syntax to Python for annotating the types of variables including class variables and instance variables:
primes: List[int] = []
captain: str # Note: no initial value!
class Starship:
stats: Dict[str, int] = {}
Just as for function annotations, the Python interpreter does not attach any particular meaning to variable annotations and only stores them in the
__annotations__
attribute of a class or module.
In contrast to variable declarations in statically typed languages, the goal of annotation syntax is to provide an easy way to specify structured type metadata for third party tools and libraries via the abstract syntax tree and the
__annotations__
属性。
PEP 515 adds the ability to use underscores in numeric literals for improved readability. For example:
>>> 1_000_000_000_000_000
1000000000000000
>>> 0x_FF_FF_FF_FF
4294967295
Single underscores are allowed between digits and after any base specifier. Leading, trailing, or multiple underscores in a row are not allowed.
string formatting
language also now has support for the
'_'
option to signal the use of an underscore for a thousands separator for floating point presentation types and for integer presentation type
'd'
. For integer presentation types
'b'
,
'o'
,
'x'
,和
'X'
, underscores will be inserted every 4 digits:
>>> '{:_}'.format(1000000)
'1_000_000'
>>> '{:_x}'.format(0xFFFFFFFF)
'ffff_ffff'
另请参阅
PEP 492
introduced support for native coroutines and
async
/
await
syntax to Python 3.5. A notable limitation of the Python 3.5 implementation is that it was not possible to use
await
and
yield
in the same function body. In Python 3.6 this restriction has been lifted, making it possible to define
asynchronous generators
:
async def ticker(delay, to):
"""Yield numbers from 0 to *to* every *delay* seconds."""
for i in range(to):
yield i
await asyncio.sleep(delay)
The new syntax allows for faster and more concise code.
另请参阅
PEP 530
adds support for using
async
for
in list, set, dict comprehensions and generator expressions:
result = [i async for i in aiter() if i % 2]
Additionally,
await
expressions are supported in all kinds of comprehensions:
result = [await fun() for fun in funcs if await condition()]
另请参阅
It is now possible to customize subclass creation without using a metaclass. The new
__init_subclass__
classmethod will be called on the base class whenever a new subclass is created:
class PluginBase:
subclasses = []
def __init_subclass__(cls, **kwargs):
super().__init_subclass__(**kwargs)
cls.subclasses.append(cls)
class Plugin1(PluginBase):
pass
class Plugin2(PluginBase):
pass
In order to allow zero-argument
super()
calls to work correctly from
__init_subclass__()
implementations, custom metaclasses must ensure that the new
__classcell__
namespace entry is propagated to
type.__new__
(as described in
Creating the class object
).
PEP 487
extends the descriptor protocol to include the new optional
__set_name__()
method. Whenever a new class is defined, the new method will be called on all descriptors included in the definition, providing them with a reference to the class being defined and the name given to the descriptor within the class namespace. In other words, instances of descriptors can now know the attribute name of the descriptor in the owner class:
class IntField:
def __get__(self, instance, owner):
return instance.__dict__[self.name]
def __set__(self, instance, value):
if not isinstance(value, int):
raise ValueError(f'expecting integer in {self.name}')
instance.__dict__[self.name] = value
# this is the new initializer:
def __set_name__(self, owner, name):
self.name = name
class Model:
int_field = IntField()
File system paths have historically been represented as
str
or
bytes
objects. This has led to people who write code which operate on file system paths to assume that such objects are only one of those two types (an
int
representing a file descriptor does not count as that is not a file path). Unfortunately that assumption prevents alternative object representations of file system paths like
pathlib
from working with pre-existing code, including Python’s standard library.
To fix this situation, a new interface represented by
os.PathLike
has been defined. By implementing the
__fspath__()
method, an object signals that it represents a path. An object can then provide a low-level representation of a file system path as a
str
or
bytes
object. This means an object is considered
像路径
if it implements
os.PathLike
or is a
str
or
bytes
object which represents a file system path. Code can use
os.fspath()
,
os.fsdecode()
,或
os.fsencode()
to explicitly get a
str
and/or
bytes
representation of a path-like object.
The built-in
open()
function has been updated to accept
os.PathLike
objects, as have all relevant functions in the
os
and
os.path
modules, and most other functions and classes in the standard library. The
os.DirEntry
class and relevant classes in
pathlib
have also been updated to implement
os.PathLike
.
The hope is that updating the fundamental functions for operating on file system paths will lead to third-party code to implicitly support all
像路径对象
without any code changes, or at least very minimal ones (e.g. calling
os.fspath()
at the beginning of code before operating on a path-like object).
Here are some examples of how the new interface allows for
pathlib.Path
to be used more easily and transparently with pre-existing code:
>>> import pathlib
>>> with open(pathlib.Path("README")) as f:
... contents = f.read()
...
>>> import os.path
>>> os.path.splitext(pathlib.Path("some_file.txt"))
('some_file', '.txt')
>>> os.path.join("/a/b", pathlib.Path("c"))
'/a/b/c'
>>> import os
>>> os.fspath(pathlib.Path("some_file.txt"))
'some_file.txt'
(Implemented by Brett Cannon, Ethan Furman, Dusty Phillips, and Jelle Zijlstra.)
另请参阅
In most world locations, there have been and will be times when local clocks are moved back. In those times, intervals are introduced in which local clocks show the same time twice in the same day. In these situations, the information displayed on a local clock (or stored in a Python datetime instance) is insufficient to identify a particular moment in time.
PEP 495
adds the new
fold
attribute to instances of
datetime.datetime
and
datetime.time
classes to differentiate between two moments in time for which local times are the same:
>>> u0 = datetime(2016, 11, 6, 4, tzinfo=timezone.utc)
>>> for i in range(4):
... u = u0 + i*HOUR
... t = u.astimezone(Eastern)
... print(u.time(), 'UTC =', t.time(), t.tzname(), t.fold)
...
04:00:00 UTC = 00:00:00 EDT 0
05:00:00 UTC = 01:00:00 EDT 0
06:00:00 UTC = 01:00:00 EST 1
07:00:00 UTC = 02:00:00 EST 0
The values of the
fold
attribute have the value
0
for all instances except those that represent the second (chronologically) moment in time in an ambiguous case.
另请参阅
Representing filesystem paths is best performed with str (Unicode) rather than bytes. However, there are some situations where using bytes is sufficient and correct.
Prior to Python 3.6, data loss could result when using bytes paths on Windows. With this change, using bytes to represent paths is now supported on Windows, provided those bytes are encoded with the encoding returned by
sys.getfilesystemencoding()
, which now defaults to
'utf-8'
.
Applications that do not use str to represent paths should use
os.fsencode()
and
os.fsdecode()
to ensure their bytes are correctly encoded. To revert to the previous behaviour, set
PYTHONLEGACYWINDOWSFSENCODING
or call
sys._enablelegacywindowsfsencoding()
.
见 PEP 529 for more information and discussion of code modifications that may be required.
The default console on Windows will now accept all Unicode characters and provide correctly read str objects to Python code.
sys.stdin
,
sys.stdout
and
sys.stderr
now default to utf-8 encoding.
This change only applies when using an interactive console, and not when redirecting files or pipes. To revert to the previous behaviour for interactive console use, set
PYTHONLEGACYWINDOWSSTDIO
.
另请参阅
Attributes in a class definition body have a natural ordering: the same order in which the names appear in the source. This order is now preserved in the new class’s
__dict__
属性。
Also, the effective default class execution namespace (returned from type.__prepare__() ) is now an insertion-order-preserving mapping.
另请参阅
**kwargs
in a function signature is now guaranteed to be an insertion-order-preserving mapping.
另请参阅
dict
type now uses a “compact” representation based on
a proposal by Raymond Hettinger
which was
first implemented by PyPy
. The memory usage of the new
dict()
is between 20% and 25% smaller compared to Python 3.5.
The order-preserving aspect of this new implementation is considered an implementation detail and should not be relied upon (this may change in the future, but it is desired to have this new dict implementation in the language for a few releases before changing the language spec to mandate order-preserving semantics for all current and future Python implementations; this also helps preserve backwards-compatibility with older versions of the language where random iteration order is still in effect, e.g. Python 3.5).
(Contributed by INADA Naoki in bpo-27350 . Idea originally suggested by Raymond Hettinger .)
While Python provides extensive support to customize how code executes, one place it has not done so is in the evaluation of frame objects. If you wanted some way to intercept frame evaluation in Python there really wasn’t any way without directly manipulating function pointers for defined functions.
PEP 523 changes this by providing an API to make frame evaluation pluggable at the C level. This will allow for tools such as debuggers and JITs to intercept frame evaluation before the execution of Python code begins. This enables the use of alternative evaluation implementations for Python code, tracking frame evaluation, etc.
This API is not part of the limited C API and is marked as private to signal that usage of this API is expected to be limited and only applicable to very select, low-level use-cases. Semantics of the API will change with Python as necessary.
另请参阅
The new
PYTHONMALLOC
environment variable allows setting the Python memory allocators and installing debug hooks.
It is now possible to install debug hooks on Python memory allocators on Python compiled in release mode using
PYTHONMALLOC=debug
. Effects of debug hooks:
0xCB
0xDB
PyObject_Free()
called on a memory block allocated by
PyMem_Malloc()
.
PYMEM_DOMAIN_OBJ
(ex:
PyObject_Malloc()
) and
PYMEM_DOMAIN_MEM
(ex:
PyMem_Malloc()
) domains are called.
Checking if the GIL is held is also a new feature of Python 3.6.
见
PyMem_SetupDebugHooks()
function for debug hooks on Python memory allocators.
It is now also possible to force the usage of the
malloc()
allocator of the C library for all Python memory allocations using
PYTHONMALLOC=malloc
. This is helpful when using external memory debuggers like Valgrind on a Python compiled in release mode.
On error, the debug hooks on Python memory allocators now use the
tracemalloc
module to get the traceback where a memory block was allocated.
Example of fatal error on buffer overflow using
python3.6
-X
tracemalloc=5
(store 5 frames in traces):
Debug memory block at address p=0x7fbcd41666f8: API 'o'
4 bytes originally requested
The 7 pad bytes at p-7 are FORBIDDENBYTE, as expected.
The 8 pad bytes at tail=0x7fbcd41666fc are not all FORBIDDENBYTE (0xfb):
at tail+0: 0x02 *** OUCH
at tail+1: 0xfb
at tail+2: 0xfb
at tail+3: 0xfb
at tail+4: 0xfb
at tail+5: 0xfb
at tail+6: 0xfb
at tail+7: 0xfb
The block was made by call #1233329 to debug malloc/realloc.
Data at p: 1a 2b 30 00
Memory block allocated at (most recent call first):
File "test/test_bytes.py", line 323
File "unittest/case.py", line 600
File "unittest/case.py", line 648
File "unittest/suite.py", line 122
File "unittest/suite.py", line 84
Fatal Python error: bad trailing pad byte
Current thread 0x00007fbcdbd32700 (most recent call first):
File "test/test_bytes.py", line 323 in test_hex
File "unittest/case.py", line 600 in run
File "unittest/case.py", line 648 in __call__
File "unittest/suite.py", line 122 in run
File "unittest/suite.py", line 84 in __call__
File "unittest/suite.py", line 122 in run
File "unittest/suite.py", line 84 in __call__
...
(Contributed by Victor Stinner in bpo-26516 and bpo-26564 .)
Python can now be built
--with-dtrace
which enables static markers for the following events in the interpreter:
This can be used to instrument running interpreters in production, without the need to recompile specific debug builds or providing application-specific profiling/debugging code.
More details in Instrumenting CPython with DTrace and SystemTap .
The current implementation is tested on Linux and macOS. Additional markers may be added in the future.
(Contributed by Łukasz Langa in bpo-21590 , based on patches by Jesús Cea Avión, David Malcolm, and Nikhil Benesch.)
Some smaller changes made to the core Python language are:
global
or
nonlocal
statement must now textually appear
before the first use of the affected name in the same scope.
Previously this was a
SyntaxWarning
.
None
to indicate that the corresponding operation is not available.
For example, if a class sets
__iter__()
to
None
, the class
is not iterable.
(Contributed by Andrew Barnert and Ivan Levkivskyi in
bpo-25958
.)
"[Previous
line
repeated
{count}
more
times]"
(见
traceback
for an example).
(Contributed by Emanuel Barry in
bpo-26823
.)
ModuleNotFoundError
(subclass of
ImportError
) when it cannot find a module. Code
that currently checks for ImportError (in try-except) will still work.
(Contributed by Eric Snow in
bpo-15767
.)
super()
will now work correctly
when called from metaclass methods during class creation.
(Contributed by Martin Teichmann in
bpo-23722
.)
The main purpose of the new
secrets
module is to provide an obvious way to reliably generate cryptographically strong pseudo-random values suitable for managing secrets, such as account authentication, tokens, and similar.
警告
Note that the pseudo-random generators in the
random
module should
NOT
be used for security purposes. Use
secrets
on Python 3.6+ and
os.urandom()
on Python 3.5 and earlier.
另请参阅
Exhausted iterators of
array.array
will now stay exhausted even if the iterated array is extended. This is consistent with the behavior of other mutable sequences.
Contributed by Serhiy Storchaka in bpo-26492 .
The new
ast.Constant
AST node has been added. It can be used by external AST optimizers for the purposes of constant folding.
Contributed by Victor Stinner in bpo-26146 .
Starting with Python 3.6 the
asyncio
module is no longer provisional and its API is considered stable.
Notable changes in the
asyncio
module since Python 3.5.0 (all backported to 3.5.x due to the provisional status):
get_event_loop()
function has been changed to
always return the currently running loop when called from coroutines
and callbacks.
(Contributed by Yury Selivanov in
bpo-28613
.)
ensure_future()
function and all functions that
use it, such as
loop.run_until_complete()
,
now accept all kinds of
awaitable objects
.
(Contributed by Yury Selivanov.)
run_coroutine_threadsafe()
function to submit
coroutines to event loops from other threads.
(Contributed by Vincent Michel.)
Transport.is_closing()
method to check if the transport is closing or closed.
(Contributed by Yury Selivanov.)
loop.create_server()
method can now accept a list of hosts.
(Contributed by Yann Sionneau.)
loop.create_future()
method to create Future objects. This allows alternative event
loop implementations, such as
uvloop
, to provide a faster
asyncio.Future
实现。
(Contributed by Yury Selivanov in
bpo-27041
.)
loop.get_exception_handler()
method to get the current exception handler.
(Contributed by Yury Selivanov in
bpo-27040
.)
StreamReader.readuntil()
method to read data from the stream until a separator bytes
sequence appears.
(Contributed by Mark Korenberg.)
StreamReader.readexactly()
has been improved.
(Contributed by Mark Korenberg in
bpo-28370
.)
loop.getaddrinfo()
method is optimized to avoid calling the system
getaddrinfo
function if the address is already resolved.
(Contributed by A. Jesse Jiryu Davis.)
loop.stop()
method has been changed to stop the loop immediately after
the current iteration. Any new callbacks scheduled as a result
of the last iteration will be discarded.
(Contributed by Guido van Rossum in
bpo-25593
.)
Future.set_exception
will now raise
TypeError
when passed an instance of
the
StopIteration
异常。
(Contributed by Chris Angelico in
bpo-26221
.)
loop.connect_accepted_socket()
method to be used by servers that accept connections outside of asyncio,
but that use asyncio to handle them.
(Contributed by Jim Fulton in
bpo-27392
.)
TCP_NODELAY
flag is now set for all TCP transports by default.
(Contributed by Yury Selivanov in
bpo-27456
.)
loop.shutdown_asyncgens()
to properly close pending asynchronous generators before closing the
loop.
(Contributed by Yury Selivanov in
bpo-28003
.)
Future
and
Task
classes now have an optimized C implementation which makes asyncio
code up to 30% faster.
(Contributed by Yury Selivanov and INADA Naoki in
bpo-26081
and
bpo-28544
.)
b2a_base64()
function now accepts an optional
newline
keyword argument to control whether the newline character is appended to the return value. (Contributed by Victor Stinner in
bpo-25357
.)
The new
cmath.tau
(
τ
) constant has been added. (Contributed by Lisa Roach in
bpo-12345
, see
PEP 628
for details.)
New constants:
cmath.inf
and
cmath.nan
to match
math.inf
and
math.nan
, and also
cmath.infj
and
cmath.nanj
to match the format used by complex repr. (Contributed by Mark Dickinson in
bpo-23229
.)
The new
Collection
abstract base class has been added to represent sized iterable container classes. (Contributed by Ivan Levkivskyi, docs by Neil Girdhar in
bpo-27598
.)
The new
Reversible
abstract base class represents iterable classes that also provide the
__reversed__()
method. (Contributed by Ivan Levkivskyi in
bpo-25987
.)
The new
AsyncGenerator
abstract base class represents asynchronous generators. (Contributed by Yury Selivanov in
bpo-28720
.)
namedtuple()
function now accepts an optional keyword argument
模块
, which, when specified, is used for the
__module__
attribute of the returned named tuple class. (Contributed by Raymond Hettinger in
bpo-17941
.)
verbose
and
rename
arguments for
namedtuple()
are now keyword-only. (Contributed by Raymond Hettinger in
bpo-25628
.)
Recursive
collections.deque
instances can now be pickled. (Contributed by Serhiy Storchaka in
bpo-26482
.)
ThreadPoolExecutor
class constructor now accepts an optional
thread_name_prefix
argument to make it possible to customize the names of the threads created by the pool. (Contributed by Gregory P. Smith in
bpo-27664
.)
contextlib.AbstractContextManager
class has been added to provide an abstract base class for context managers. It provides a sensible default implementation for
__enter__()
which returns
self
and leaves
__exit__()
an abstract method. A matching class has been added to the
typing
module as
typing.ContextManager
. (Contributed by Brett Cannon in
bpo-25609
.)
datetime
and
time
classes have the new
fold
attribute used to disambiguate local time when necessary. Many functions in the
datetime
have been updated to support local time disambiguation. See
Local Time Disambiguation
section for more information. (Contributed by Alexander Belopolsky in
bpo-24773
.)
datetime.strftime()
and
date.strftime()
methods now support ISO 8601 date directives
%G
,
%u
and
%V
. (Contributed by Ashley Anderson in
bpo-12006
.)
datetime.isoformat()
function now accepts an optional
timespec
argument that specifies the number of additional components of the time value to include. (Contributed by Alessandro Cucci and Alexander Belopolsky in
bpo-19475
.)
datetime.combine()
now accepts an optional
tzinfo
argument. (Contributed by Alexander Belopolsky in
bpo-27661
.)
New
Decimal.as_integer_ratio()
method that returns a pair
(n,
d)
of integers that represent the given
Decimal
instance as a fraction, in lowest terms and with a positive denominator:
>>> Decimal('-3.14').as_integer_ratio()
(-157, 50)
(Contributed by Stefan Krah amd Mark Dickinson in bpo-25928 .)
default_format
attribute has been removed from
distutils.command.sdist.sdist
和
formats
attribute defaults to
['gztar']
. Although not anticipated, any code relying on the presence of
default_format
may need to be adapted. See
bpo-27819
了解更多细节。
The new email API, enabled via the
policy
keyword to various constructors, is no longer provisional. The
email
documentation has been reorganized and rewritten to focus on the new API, while retaining the old documentation for the legacy API. (Contributed by R. David Murray in
bpo-24277
.)
email.mime
classes now all accept an optional
policy
keyword. (Contributed by Berker Peksag in
bpo-27331
.)
DecodedGenerator
now supports the
policy
keyword.
There is a new
policy
attribute,
message_factory
, that controls what class is used by default when the parser creates new message objects. For the
email.policy.compat32
policy this is
Message
, for the new policies it is
EmailMessage
. (Contributed by R. David Murray in
bpo-20476
.)
On Windows, added the
'oem'
encoding to use
CP_OEMCP
,和
'ansi'
alias for the existing
'mbcs'
encoding, which uses the
CP_ACP
code page. (Contributed by Steve Dower in
bpo-27959
.)
Two new enumeration base classes have been added to the
enum
模块:
Flag
and
IntFlags
. Both are used to define constants that can be combined using the bitwise operators. (Contributed by Ethan Furman in
bpo-23591
.)
Many standard library modules have been updated to use the
IntFlags
class for their constants.
The new
enum.auto
value can be used to assign values to enum members automatically:
>>> from enum import Enum, auto
>>> class Color(Enum):
... red = auto()
... blue = auto()
... green = auto()
...
>>> list(Color)
[<Color.red: 1>, <Color.blue: 2>, <Color.green: 3>]
On Windows, the
faulthandler
module now installs a handler for Windows exceptions: see
faulthandler.enable()
. (Contributed by Victor Stinner in
bpo-23848
.)
hook_encoded()
now supports the
errors
argument. (Contributed by Joseph Hackman in
bpo-25788
.)
hashlib
supports OpenSSL 1.1.0. The minimum recommend version is 1.0.2. (Contributed by Christian Heimes in
bpo-26470
.)
BLAKE2 hash functions were added to the module.
blake2b()
and
blake2s()
are always available and support the full feature set of BLAKE2. (Contributed by Christian Heimes in
bpo-26798
based on code by Dmitry Chestnykh and Samuel Neves. Documentation written by Dmitry Chestnykh.)
The SHA-3 hash functions
sha3_224()
,
sha3_256()
,
sha3_384()
,
sha3_512()
, and SHAKE hash functions
shake_128()
and
shake_256()
were added. (Contributed by Christian Heimes in
bpo-16113
. Keccak Code Package by Guido Bertoni, Joan Daemen, Michaël Peeters, Gilles Van Assche, and Ronny Van Keer.)
The password-based key derivation function
scrypt()
is now available with OpenSSL 1.1.0 and newer. (Contributed by Christian Heimes in
bpo-27928
.)
HTTPConnection.request()
and
endheaders()
both now support chunked encoding request bodies. (Contributed by Demian Brecht and Rolf Krahl in
bpo-12319
.)
The idlelib package is being modernized and refactored to make IDLE look and work better and to make the code easier to understand, test, and improve. Part of making IDLE look better, especially on Linux and Mac, is using ttk widgets, mostly in the dialogs. As a result, IDLE no longer runs with tcl/tk 8.4. It now requires tcl/tk 8.5 or 8.6. We recommend running the latest release of either.
‘Modernizing’ includes renaming and consolidation of idlelib modules. The renaming of files with partial uppercase names is similar to the renaming of, for instance, Tkinter and TkFont to tkinter and tkinter.font in 3.0. As a result, imports of idlelib files that worked in 3.5 will usually not work in 3.6. At least a module name change will be needed (see idlelib/README.txt), sometimes more. (Name changes contributed by Al Swiegart and Terry Reedy in bpo-24225 . Most idlelib patches since have been and will be part of the process.)
In compensation, the eventual result with be that some idlelib classes will be easier to use, with better APIs and docstrings explaining them. Additional useful information will be added to idlelib when available.
New in 3.6.2:
Multiple fixes for autocompletion. (Contributed by Louie Lu in bpo-15786 .)
New in 3.6.3:
Module Browser (on the File menu, formerly called Class Browser), now displays nested functions and classes in addition to top-level functions and classes. (Contributed by Guilherme Polo, Cheryl Sabella, and Terry Jan Reedy in bpo-1612262 .)
The IDLE features formerly implemented as extensions have been reimplemented as normal features. Their settings have been moved from the Extensions tab to other dialog tabs. (Contributed by Charles Wohlganger and Terry Jan Reedy in bpo-27099 .)
The Settings dialog (Options, Configure IDLE) has been partly rewritten to improve both appearance and function. (Contributed by Cheryl Sabella and Terry Jan Reedy in multiple issues.)
New in 3.6.4:
The font sample now includes a selection of non-Latin characters so that users can better see the effect of selecting a particular font. (Contributed by Terry Jan Reedy in bpo-13802 .) The sample can be edited to include other characters. (Contributed by Serhiy Storchaka in bpo-31860 .)
New in 3.6.6:
Editor code context option revised. Box displays all context lines up to maxlines. Clicking on a context line jumps the editor to that line. Context colors for custom themes is added to Highlights tab of Settings dialog. (Contributed by Cheryl Sabella and Terry Jan Reedy in bpo-33642 , bpo-33768 ,和 bpo-33679 .)
On Windows, a new API call tells Windows that tk scales for DPI. On Windows 8.1+ or 10, with DPI compatibility properties of the Python binary unchanged, and a monitor resolution greater than 96 DPI, this should make text and lines sharper. It should otherwise have no effect. (Contributed by Terry Jan Reedy in bpo-33656 .)
New in 3.6.7:
Output over N lines (50 by default) is squeezed down to a button. N can be changed in the PyShell section of the General page of the Settings dialog. Fewer, but possibly extra long, lines can be squeezed by right clicking on the output. Squeezed output can be expanded in place by double-clicking the button or into the clipboard or a separate window by right-clicking the button. (Contributed by Tal Einat in bpo-1529353 .)
Import now raises the new exception
ModuleNotFoundError
(subclass of
ImportError
) when it cannot find a module. Code that current checks for
ImportError
(in try-except) will still work. (Contributed by Eric Snow in
bpo-15767
.)
importlib.util.LazyLoader
now calls
create_module()
on the wrapped loader, removing the restriction that
importlib.machinery.BuiltinImporter
and
importlib.machinery.ExtensionFileLoader
couldn’t be used with
importlib.util.LazyLoader
.
importlib.util.cache_from_source()
,
importlib.util.source_from_cache()
,和
importlib.util.spec_from_file_location()
now accept a
像路径对象
.
inspect.signature()
function now reports the implicit
.0
parameters generated by the compiler for comprehension and generator expression scopes as if they were positional-only parameters called
implicit0
. (Contributed by Jelle Zijlstra in
bpo-19611
.)
To reduce code churn when upgrading from Python 2.7 and the legacy
inspect.getargspec()
API, the previously documented deprecation of
inspect.getfullargspec()
has been reversed. While this function is convenient for single/source Python 2/3 code bases, the richer
inspect.signature()
interface remains the recommended approach for new code. (Contributed by Nick Coghlan in
bpo-27172
)
json.load()
and
json.loads()
now support binary input. Encoded JSON should be represented using either UTF-8, UTF-16, or UTF-32. (Contributed by Serhiy Storchaka in
bpo-17909
.)
The new
WatchedFileHandler.reopenIfNeeded()
method has been added to add the ability to check if the log file needs to be reopened. (Contributed by Marian Horban in
bpo-24884
.)
The tau (
τ
) constant has been added to the
math
and
cmath
modules. (Contributed by Lisa Roach in
bpo-12345
, see
PEP 628
for details.)
Proxy Objects
returned by
multiprocessing.Manager()
can now be nested. (Contributed by Davin Potts in
bpo-6766
.)
See the summary of
PEP 519
for details on how the
os
and
os.path
modules now support
像路径对象
.
scandir()
now supports
bytes
paths on Windows.
A new
close()
method allows explicitly closing a
scandir()
iterator. The
scandir()
iterator now supports the
上下文管理器
protocol. If a
scandir()
iterator is neither exhausted nor explicitly closed a
ResourceWarning
will be emitted in its destructor. (Contributed by Serhiy Storchaka in
bpo-25994
.)
在 Linux,
os.urandom()
now blocks until the system urandom entropy pool is initialized to increase the security. See the
PEP 524
for the rationale.
The Linux
getrandom()
syscall (get random bytes) is now exposed as the new
os.getrandom()
function. (Contributed by Victor Stinner, part of the
PEP 524
)
pathlib
now supports
像路径对象
. (Contributed by Brett Cannon in
bpo-27186
.)
See the summary of PEP 519 了解细节。
Pdb
class constructor has a new optional
readrc
argument to control whether
.pdbrc
files should be read.
Objects that need
__new__
called with keyword arguments can now be pickled using
pickle protocols
older than protocol version 4. Protocol version 4 already supports this case. (Contributed by Serhiy Storchaka in
bpo-24164
.)
pickletools.dis()
now outputs the implicit memo index for the
MEMOIZE
opcode. (Contributed by Serhiy Storchaka in
bpo-25382
.)
pydoc
module has learned to respect the
MANPAGER
environment variable. (Contributed by Matthias Klose in
bpo-8637
.)
help()
and
pydoc
can now list named tuple fields in the order they were defined rather than alphabetically. (Contributed by Raymond Hettinger in
bpo-24879
.)
The new
choices()
function returns a list of elements of specified size from the given population with optional weights. (Contributed by Raymond Hettinger in
bpo-18844
.)
Added support of modifier spans in regular expressions. Examples:
'(?i:p)ython'
matches
'python'
and
'Python'
, but not
'PYTHON'
;
'(?i)g(?-i:v)r'
matches
'GvR'
and
'gvr'
, but not
'GVR'
. (Contributed by Serhiy Storchaka in
bpo-433028
.)
Match object groups can be accessed by
__getitem__
, which is equivalent to
group()
. So
mo['name']
is now equivalent to
mo.group('name')
. (Contributed by Eric Smith in
bpo-24454
.)
Match
objects now support
index-like
对象
as group indices. (Contributed by Jeroen Demeyer and Xiang Zhang in
bpo-27177
.)
添加
set_auto_history()
to enable or disable automatic addition of input to the history list. (Contributed by Tyler Crompton in
bpo-26870
.)
Private and special attribute names now are omitted unless the prefix starts with underscores. A space or a colon is added after some completed keywords. (Contributed by Serhiy Storchaka in bpo-25011 and bpo-25209 .)
shlex
has much
improved shell compatibility
through the new
punctuation_chars
argument to control which characters are treated as punctuation. (Contributed by Vinay Sajip in
bpo-1521950
.)
When specifying paths to add to
sys.path
在
.pth
file, you may now specify file paths on top of directories (e.g. zip files). (Contributed by Wolfgang Langner in
bpo-26587
).
sqlite3.Cursor.lastrowid
now supports the
REPLACE
statement. (Contributed by Alex LordThorsen in
bpo-16864
.)
ioctl()
function now supports the
SIO_LOOPBACK_FAST_PATH
control code. (Contributed by Daniel Stokes in
bpo-26536
.)
getsockopt()
constants
SO_DOMAIN
,
SO_PROTOCOL
,
SO_PEERSEC
,和
SO_PASSSEC
are now supported. (Contributed by Christian Heimes in
bpo-26907
.)
setsockopt()
now supports the
setsockopt(level,
optname,
None,
optlen:
int)
form. (Contributed by Christian Heimes in
bpo-27744
.)
The socket module now supports the address family
AF_ALG
to interface with Linux Kernel crypto API.
ALG_*
,
SOL_ALG
and
sendmsg_afalg()
were added. (Contributed by Christian Heimes in
bpo-27744
with support from Victor Stinner.)
New Linux constants
TCP_USER_TIMEOUT
and
TCP_CONGESTION
were added. (Contributed by Omar Sandoval, issue:
26273
).
Servers based on the
socketserver
module, including those defined in
http.server
,
xmlrpc.server
and
wsgiref.simple_server
, now support the
上下文管理器
protocol. (Contributed by Aviv Palivoda in
bpo-26404
.)
wfile
attribute of
StreamRequestHandler
classes now implements the
io.BufferedIOBase
writable interface. In particular, calling
write()
is now guaranteed to send the data in full. (Contributed by Martin Panter in
bpo-26721
.)
ssl
supports OpenSSL 1.1.0. The minimum recommend version is 1.0.2. (Contributed by Christian Heimes in
bpo-26470
.)
3DES has been removed from the default cipher suites and ChaCha20 Poly1305 cipher suites have been added. (Contributed by Christian Heimes in bpo-27850 and bpo-27766 .)
SSLContext
has better default configuration for options and ciphers. (Contributed by Christian Heimes in
bpo-28043
.)
SSL session can be copied from one client-side connection to another with the new
SSLSession
class. TLS session resumption can speed up the initial handshake, reduce latency and improve performance (Contributed by Christian Heimes in
bpo-19500
based on a draft by Alex Warhawk.)
The new
get_ciphers()
method can be used to get a list of enabled ciphers in order of cipher priority.
All constants and flags have been converted to
IntEnum
and
IntFlags
. (Contributed by Christian Heimes in
bpo-28025
.)
Server and client-side specific TLS protocols for
SSLContext
were added. (Contributed by Christian Heimes in
bpo-28085
.)
添加
SSLContext.post_handshake_auth
to enable and
ssl.SSLSocket.verify_client_post_handshake()
to initiate TLS 1.3 post-handshake authentication. (Contributed by Christian Heimes in
bpo-34670
.)
A new
harmonic_mean()
function has been added. (Contributed by Steven D’Aprano in
bpo-27181
.)
struct
now supports IEEE 754 half-precision floats via the
'e'
format specifier. (Contributed by Eli Stevens, Mark Dickinson in
bpo-11734
.)
subprocess.Popen
destructor now emits a
ResourceWarning
warning if the child process is still running. Use the context manager protocol (
with
proc:
...
) or explicitly call the
wait()
method to read the exit status of the child process. (Contributed by Victor Stinner in
bpo-26741
.)
subprocess.Popen
constructor and all functions that pass arguments through to it now accept
encoding
and
errors
arguments. Specifying either of these will enable text mode for the
stdin
,
stdout
and
stderr
streams. (Contributed by Steve Dower in
bpo-6135
.)
The new
getfilesystemencodeerrors()
function returns the name of the error mode used to convert between Unicode filenames and bytes filenames. (Contributed by Steve Dower in
bpo-27781
.)
On Windows the return value of the
getwindowsversion()
function now includes the
platform_version
field which contains the accurate major version, minor version and build number of the current operating system, rather than the version that is being emulated for the process (Contributed by Steve Dower in
bpo-27932
.)
struct_time
attributes
tm_gmtoff
and
tm_zone
are now available on all platforms.
The new
Timer.autorange()
convenience method has been added to call
Timer.timeit()
repeatedly so that the total run time is greater or equal to 200 milliseconds. (Contributed by Steven D’Aprano in
bpo-6422
.)
timeit
now warns when there is substantial (4x) variance between best and worst times. (Contributed by Serhiy Storchaka in
bpo-23552
.)
Added methods
trace_add()
,
trace_remove()
and
trace_info()
在
tkinter.Variable
class. They replace old methods
trace_variable()
,
trace()
,
trace_vdelete()
and
trace_vinfo()
that use obsolete Tcl commands and might not work in future versions of Tcl. (Contributed by Serhiy Storchaka in
bpo-22115
).
Both the traceback module and the interpreter’s builtin exception display now abbreviate long sequences of repeated lines in tracebacks as shown in the following example:
>>> def f(): f()
...
>>> f()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 1, in f
File "<stdin>", line 1, in f
File "<stdin>", line 1, in f
[Previous line repeated 995 more times]
RecursionError: maximum recursion depth exceeded
(Contributed by Emanuel Barry in bpo-26823 .)
tracemalloc
module now supports tracing memory allocations in multiple different address spaces.
The new
DomainFilter
filter class has been added to filter block traces by their address space (domain).
(Contributed by Victor Stinner in bpo-26588 .)
Since the
typing
module is
provisional
, all changes introduced in Python 3.6 have also been backported to Python 3.5.x.
typing
module has a much improved support for generic type aliases. For example
Dict[str,
Tuple[S,
T]]
is now a valid type annotation. (Contributed by Guido van Rossum in
Github #195
.)
typing.ContextManager
class has been added for representing
contextlib.AbstractContextManager
. (Contributed by Brett Cannon in
bpo-25609
.)
typing.Collection
class has been added for representing
collections.abc.Collection
. (Contributed by Ivan Levkivskyi in
bpo-27598
.)
typing.ClassVar
type construct has been added to mark class variables. As introduced in
PEP 526
, a variable annotation wrapped in ClassVar indicates that a given attribute is intended to be used as a class variable and should not be set on instances of that class. (Contributed by Ivan Levkivskyi in
Github #280
.)
A new
TYPE_CHECKING
constant that is assumed to be
True
by the static type chekers, but is
False
at runtime. (Contributed by Guido van Rossum in
Github #230
.)
A new
NewType()
helper function has been added to create lightweight distinct types for annotations:
from typing import NewType
UserId = NewType('UserId', int)
some_id = UserId(524313)
The static type checker will treat the new type as if it were a subclass of the original type. (Contributed by Ivan Levkivskyi in Github #189 .)
unicodedata
module now uses data from
Unicode 9.0.0
. (Contributed by Benjamin Peterson.)
Mock
class has the following improvements:
Mock.assert_called()
and
Mock.assert_called_once()
to check if the mock object
was called.
(Contributed by Amit Saha in
bpo-26323
.)
Mock.reset_mock()
method
now has two optional keyword only arguments:
return_value
and
side_effect
.
(Contributed by Kushal Das in
bpo-21271
.)
If a HTTP request has a file or iterable body (other than a bytes object) but no
Content-Length
header, rather than throwing an error,
AbstractHTTPHandler
now falls back to use chunked transfer encoding. (Contributed by Demian Brecht and Rolf Krahl in
bpo-12319
.)
RobotFileParser
now supports the
Crawl-delay
and
Request-rate
extensions. (Contributed by Nikolay Bogoychev in
bpo-16099
.)
venv
accepts a new parameter
--prompt
. This parameter provides an alternative prefix for the virtual environment. (Proposed by Łukasz Balcerzak and ported to 3.6 by Stéphane Wirtel in
bpo-22829
.)
A new optional
source
parameter has been added to the
warnings.warn_explicit()
function: the destroyed object which emitted a
ResourceWarning
. A
source
attribute has also been added to
warnings.WarningMessage
(contributed by Victor Stinner in
bpo-26568
and
bpo-26567
).
当
ResourceWarning
warning is logged, the
tracemalloc
module is now used to try to retrieve the traceback where the destroyed object was allocated.
Example with the script
example.py
:
import warnings
def func():
return open(__file__)
f = func()
f = None
Output of the command
python3.6
-Wd
-X
tracemalloc=5
example.py
:
example.py:7: ResourceWarning: unclosed file <_io.TextIOWrapper name='example.py' mode='r' encoding='UTF-8'>
f = None
Object allocated at (most recent call first):
File "example.py", lineno 4
return open(__file__)
File "example.py", lineno 6
f = func()
The “Object allocated at” traceback is new and is only displayed if
tracemalloc
is tracing Python memory allocations and if the
warnings
module was already imported.
Allowed keyword arguments to be passed to
Beep
,
MessageBeep
,和
PlaySound
(
bpo-27982
).
xmlrpc.client
module now supports unmarshalling additional data types used by the Apache XML-RPC implementation for numerics and
None
. (Contributed by Serhiy Storchaka in
bpo-26885
.)
A new
ZipInfo.from_file()
class method allows making a
ZipInfo
instance from a filesystem file. A new
ZipInfo.is_dir()
method can be used to check if the
ZipInfo
instance represents a directory. (Contributed by Thomas Kluyver in
bpo-26039
.)
ZipFile.open()
method can now be used to write data into a ZIP file, as well as for extracting data. (Contributed by Thomas Kluyver in
bpo-26039
.)
compress()
and
decompress()
functions now accept keyword arguments. (Contributed by Aviv Palivoda in
bpo-26243
and Xiang Zhang in
bpo-16764
respectively.)
asyncio.Future
class now has an optimized C implementation.
(Contributed by Yury Selivanov and INADA Naoki in
bpo-26081
.)
asyncio.Task
class now has an optimized
C implementation. (Contributed by Yury Selivanov in
bpo-28544
.)
typing
模块
(such as caching of generic types) allow up to 30 times performance
improvements and reduced memory footprint.
surrogateescape
,
ignore
and
replace
(Contributed
by Victor Stinner in
bpo-24870
).
surrogateescape
(Contributed by Victor Stinner in
bpo-25227
).
ignore
,
replace
,
surrogateescape
,
surrogatepass
(Contributed
by Victor Stinner in
bpo-25267
).
ignore
,
replace
and
surrogateescape
(Contributed
by Victor Stinner in
bpo-25301
).
bytes
%
args
is now up to 2 times faster. (Contributed by Victor Stinner
in
bpo-25349
).
bytearray
%
args
is now between 2.5 and 5 times faster. (Contributed by
Victor Stinner in
bpo-25399
).
bytes.fromhex()
and
bytearray.fromhex()
: they are now
between 2x and 3.5x faster. (Contributed by Victor Stinner in
bpo-25401
).
bytes.replace(b'',
b'.')
and
bytearray.replace(b'',
b'.')
:
up to 80% faster. (Contributed by Josh Snider in
bpo-26574
).
PyMem_Malloc()
domain
(
PYMEM_DOMAIN_MEM
) now use the
pymalloc memory allocator
而不是
malloc()
function of the C library. The
pymalloc allocator is optimized for objects smaller or equal to 512 bytes
with a short lifetime, and use
malloc()
for larger memory blocks.
(Contributed by Victor Stinner in
bpo-26249
).
pickle.load()
and
pickle.loads()
are now up to 10% faster when
deserializing many small objects (Contributed by Victor Stinner in
bpo-27056
).
glob()
and
iglob()
functions in the
glob
module; they are now about 3–6 times faster.
(Contributed by Serhiy Storchaka in
bpo-25596
).
pathlib
by using
os.scandir()
;
it is now about 1.5–4 times faster.
(Contributed by Serhiy Storchaka in
bpo-26032
).
xml.etree.ElementTree
parsing, iteration and deepcopy performance
has been significantly improved.
(Contributed by Serhiy Storchaka in
bpo-25638
,
bpo-25873
,
and
bpo-25869
.)
fractions.Fraction
instances from floats and
decimals is now 2 to 3 times faster.
(Contributed by Serhiy Storchaka in
bpo-25971
.)
PY_LONG_LONG
.
更多信息,见
PEP 7
and
bpo-17884
.
--enable-optimizations
configure flag has been added. Turning it on
will activate expensive optimizations like PGO.
(Original patch by Alecsandru Patrascu of Intel in
bpo-26359
.)
PYMEM_DOMAIN_OBJ
(ex:
PyObject_Malloc()
) and
PYMEM_DOMAIN_MEM
(ex:
PyMem_Malloc()
) domains are called.
Py_FinalizeEx()
API which indicates if flushing buffered data
failed.
(Contributed by Martin Panter in
bpo-5319
.)
PyArg_ParseTupleAndKeywords()
now supports
positional-only
参数
. Positional-only parameters are
defined by empty names.
(Contributed by Serhiy Storchaka in
bpo-26282
).
PyTraceback_Print
method now abbreviates long sequences of repeated lines
as
"[Previous
line
repeated
{count}
more
times]"
.
(Contributed by Emanuel Barry in
bpo-26823
.)
PyErr_SetImportErrorSubclass()
function allows for
specifying a subclass of
ImportError
to raise.
(Contributed by Eric Snow in
bpo-15767
.)
PyErr_ResourceWarning()
function can be used to generate
a
ResourceWarning
providing the source of the resource allocation.
(Contributed by Victor Stinner in
bpo-26567
.)
PyOS_FSPath()
function returns the file system
representation of a
像路径对象
.
(Contributed by Brett Cannon in
bpo-27186
.)
PyUnicode_FSConverter()
and
PyUnicode_FSDecoder()
functions will now accept
像路径对象
.
When
--version
(short form:
-V
) is supplied twice, Python prints
sys.version
for detailed information.
$ ./python -VV
Python 3.6.0b4+ (3.6:223967b49e49+, Nov 21 2016, 20:55:04)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)]
async
and
await
are not recommended to be used as variable, class, function or module names. Introduced by
PEP 492
in Python 3.5, they will become proper keywords in Python 3.7. Starting in Python 3.6, the use of
async
or
await
as names will generate a
DeprecationWarning
.
Raising the
StopIteration
exception inside a generator will now generate a
DeprecationWarning
, and will trigger a
RuntimeError
in Python 3.7. See
PEP 479: Change StopIteration handling inside generators
了解细节。
__aiter__()
method is now expected to return an asynchronous iterator directly instead of returning an awaitable as previously. Doing the former will trigger a
DeprecationWarning
. Backward compatibility will be removed in Python 3.7. (Contributed by Yury Selivanov in
bpo-27243
.)
A backslash-character pair that is not a valid escape sequence now generates a
DeprecationWarning
. Although this will eventually become a
SyntaxError
, that will not be for several Python releases. (Contributed by Emanuel Barry in
bpo-27364
.)
When performing a relative import, falling back on
__name__
and
__path__
from the calling module when
__spec__
or
__package__
are not defined now raises an
ImportWarning
. (Contributed by Rose Ames in
bpo-25791
.)
asynchat
has been deprecated in favor of
asyncio
. (Contributed by Mariatta in
bpo-25002
.)
asyncore
has been deprecated in favor of
asyncio
. (Contributed by Mariatta in
bpo-25002
.)
不像其它
dbm
implementations, the
dbm.dumb
module creates databases with the
'rw'
mode and allows modifying the database opened with the
'r'
mode. This behavior is now deprecated and will be removed in 3.8. (Contributed by Serhiy Storchaka in
bpo-21708
.)
The undocumented
extra_path
argument to the
分发
constructor is now considered deprecated and will raise a warning if set. Support for this parameter will be removed in a future Python release. See
bpo-27919
了解细节。
The support of non-integer arguments in
getgrgid()
has been deprecated. (Contributed by Serhiy Storchaka in
bpo-26129
.)
importlib.machinery.SourceFileLoader.load_module()
and
importlib.machinery.SourcelessFileLoader.load_module()
methods are now deprecated. They were the only remaining implementations of
importlib.abc.Loader.load_module()
in
importlib
that had not been deprecated in previous versions of Python in favour of
importlib.abc.Loader.exec_module()
.
importlib.machinery.WindowsRegistryFinder
class is now deprecated. As of 3.6.0, it is still added to
sys.meta_path
by default (on Windows), but this may change in future releases.
Undocumented support of general
像字节对象
as paths in
os
functions,
compile()
and similar functions is now deprecated. (Contributed by Serhiy Storchaka in
bpo-25791
and
bpo-26754
.)
Support for inline flags
(?letters)
in the middle of the regular expression has been deprecated and will be removed in a future Python version. Flags at the start of a regular expression are still allowed. (Contributed by Serhiy Storchaka in
bpo-22493
.)
OpenSSL 0.9.8, 1.0.0 and 1.0.1 are deprecated and no longer supported. In the future the
ssl
module will require at least OpenSSL 1.0.2 or 1.1.0.
SSL-related arguments like
certfile
,
keyfile
and
check_hostname
in
ftplib
,
http.client
,
imaplib
,
poplib
,和
smtplib
have been deprecated in favor of
context
. (Contributed by Christian Heimes in
bpo-28022
.)
A couple of protocols and functions of the
ssl
module are now deprecated. Some features will no longer be available in future versions of OpenSSL. Other features are deprecated in favor of a different API. (Contributed by Christian Heimes in
bpo-28022
and
bpo-26470
.)
tkinter.tix
module is now deprecated.
tkinter
users should use
tkinter.ttk
代替。
xml.dom.minidom
and mod:
xml.sax
modules no longer process
external entities by default.
(Contributed by Christian Heimes in
bpo-17239
.)
Undocumented functions
PyUnicode_AsEncodedObject()
,
PyUnicode_AsDecodedObject()
,
PyUnicode_AsEncodedUnicode()
and
PyUnicode_AsDecodedUnicode()
are deprecated now. Use the
generic codec based API
代替。
--with-system-ffi
configure flag is now on by default on non-macOS UNIX platforms. It may be disabled by using
--without-system-ffi
, but using the flag is deprecated and will not be accepted in Python 3.7. macOS is unaffected by this change. Note that many OS distributors already use the
--with-system-ffi
flag when building their system Python.
'\'
and an ASCII letter in
regular expressions will now cause an error. In replacement templates for
re.sub()
they are still allowed, but deprecated.
re.LOCALE
flag can now only be used with binary patterns.
inspect.getmoduleinfo()
was removed (was deprecated since CPython 3.3).
inspect.getmodulename()
should be used for obtaining the module
name for a given path.
(Contributed by Yury Selivanov in
bpo-13248
.)
traceback.Ignore
class and
traceback.usage
,
traceback.modname
,
traceback.fullmodname
,
traceback.find_lines_from_code
,
traceback.find_lines
,
traceback.find_strings
,
traceback.find_executable_lines
methods were removed from the
traceback
module. They were undocumented methods deprecated since
Python 3.2 and equivalent functionality is available from private methods.
tk_menuBar()
and
tk_bindForTraversal()
dummy methods in
tkinter
widget classes were removed (corresponding Tk commands
were obsolete since Tk 4.0).
open()
方法源于
zipfile.ZipFile
class no longer supports the
'U'
mode (was deprecated since Python 3.4).
使用
io.TextIOWrapper
for reading compressed text files in
通用换行符
模式。
IN
,
CDROM
,
DLFCN
,
TYPES
,
CDIO
,和
STROPTS
modules have been removed. They had been available in the
platform specific
Lib/plat-*/
directories, but were chronically out of
date, inconsistently available across platforms, and unmaintained. The
script that created these modules is still available in the source
distribution at
Tools/scripts/h2py.py
.
asynchat.fifo
class has been removed.
This section lists previously described changes and other bugfixes that may require changes to your code.
COUNT_ALLOCS
,
SHOW_ALLOC_COUNT
or
SHOW_TRACK_COUNT
macros is now off by
default. It can be re-enabled using the
-X
showalloccount
选项。
It now outputs to
stderr
而不是
stdout
.
(Contributed by Serhiy Storchaka in
bpo-23034
.)
open()
will no longer allow combining the
'U'
mode flag with
'+'
. (Contributed by Jeff Balogh and John O’Connor in
bpo-2091
.)
sqlite3
no longer implicitly commits an open transaction before DDL statements.
在 Linux,
os.urandom()
now blocks until the system urandom entropy pool is initialized to increase the security.
When
importlib.abc.Loader.exec_module()
is defined,
importlib.abc.Loader.create_module()
must also be defined.
PyErr_SetImportError()
now sets
TypeError
when its
msg
argument is not set. Previously only
NULL
was returned.
The format of the
co_lnotab
attribute of code objects changed to support a negative line number delta. By default, Python does not emit bytecode with a negative line number delta. Functions using
frame.f_lineno
,
PyFrame_GetLineNumber()
or
PyCode_Addr2Line()
are not affected. Functions directly decoding
co_lnotab
should be updated to use a signed 8-bit integer type for the line number delta, but this is only required to support applications using a negative line number delta. See
Objects/lnotab_notes.txt
为
co_lnotab
format and how to decode it, and see the
PEP 511
for the rationale.
The functions in the
compileall
module now return booleans instead of
1
or
0
to represent success or failure, respectively. Thanks to booleans being a subclass of integers, this should only be an issue if you7 were doing identity checks for
1
or
0
。见
bpo-25768
.
Reading the
port
attribute of
urllib.parse.urlsplit()
and
urlparse()
results now raises
ValueError
for out-of-range values, rather than returning
None
。见
bpo-20059
.
imp
module now raises a
DeprecationWarning
而不是
PendingDeprecationWarning
.
The following modules have had missing APIs added to their
__all__
attributes to match the documented APIs:
calendar
,
cgi
,
csv
,
ElementTree
,
enum
,
fileinput
,
ftplib
,
logging
,
mailbox
,
mimetypes
,
optparse
,
plistlib
,
smtpd
,
subprocess
,
tarfile
,
threading
and
wave
. This means they will export new symbols when
import
*
is used. (Contributed by Joel Taddei and Jacek Kołodziej in
bpo-23883
.)
When performing a relative import, if
__package__
does not compare equal to
__spec__.parent
then
ImportWarning
is raised. (Contributed by Brett Cannon in
bpo-25791
.)
When a relative import is performed and no parent package is known, then
ImportError
will be raised. Previously,
SystemError
could be raised. (Contributed by Brett Cannon in
bpo-18018
.)
Servers based on the
socketserver
module, including those defined in
http.server
,
xmlrpc.server
and
wsgiref.simple_server
, now only catch exceptions derived from
Exception
. Therefore if a request handler raises an exception like
SystemExit
or
KeyboardInterrupt
,
handle_error()
is no longer called, and the exception will stop a single-threaded server. (Contributed by Martin Panter in
bpo-23430
.)
spwd.getspnam()
now raises a
PermissionError
而不是
KeyError
if the user doesn’t have privileges.
socket.socket.close()
method now raises an exception if an error (e.g.
EBADF
) was reported by the underlying system call. (Contributed by Martin Panter in
bpo-26685
.)
decode_data
argument for the
smtpd.SMTPChannel
and
smtpd.SMTPServer
constructors is now
False
by default. This means that the argument passed to
process_message()
is now a bytes object by default, and
process_message()
will be passed keyword arguments. Code that has already been updated in accordance with the deprecation warning generated by 3.5 will not be affected.
All optional arguments of the
dump()
,
dumps()
,
load()
and
loads()
functions and
JSONEncoder
and
JSONDecoder
class constructors in the
json
module are now
keyword-only
. (Contributed by Serhiy Storchaka in
bpo-18726
.)
Subclasses of
type
which don’t override
type.__new__
may no longer use the one-argument form to get the type of an object.
As part of
PEP 487
, the handling of keyword arguments passed to
type
(other than the metaclass hint,
metaclass
) is now consistently delegated to
object.__init_subclass__()
. This means that
type.__new__()
and
type.__init__()
both now accept arbitrary keyword arguments, but
object.__init_subclass__()
(which is called from
type.__new__()
) will reject them by default. Custom metaclasses accepting additional keyword arguments will need to adjust their calls to
type.__new__()
(whether direct or via
super
) accordingly.
在
distutils.command.sdist.sdist
,
default_format
attribute has been removed and is no longer honored. Instead, the gzipped tarfile format is the default on all platforms and no platform-specific selection is made. In environments where distributions are built on Windows and zip distributions are required, configure the project with a
setup.cfg
file containing the following:
[sdist]
formats=zip
This behavior has also been backported to earlier Python versions by Setuptools 26.0.0.
在
urllib.request
module and the
http.client.HTTPConnection.request()
method, if no Content-Length header field has been specified and the request body is a file object, it is now sent with HTTP 1.1 chunked encoding. If a file object has to be sent to a HTTP 1.0 server, the Content-Length value now has to be specified by the caller. (Contributed by Demian Brecht and Rolf Krahl with tweaks from Martin Panter in
bpo-12319
.)
DictReader
now returns rows of type
OrderedDict
. (Contributed by Steve Holden in
bpo-27842
.)
crypt.METHOD_CRYPT
will no longer be added to
crypt.methods
if unsupported by the platform. (Contributed by Victor Stinner in
bpo-25287
.)
verbose
and
rename
arguments for
namedtuple()
are now keyword-only. (Contributed by Raymond Hettinger in
bpo-25628
.)
在 Linux,
ctypes.util.find_library()
now looks in
LD_LIBRARY_PATH
for shared libraries. (Contributed by Vinay Sajip in
bpo-9998
.)
imaplib.IMAP4
class now handles flags containing the
']'
character in messages sent from the server to improve real-world compatibility. (Contributed by Lita Cho in
bpo-21815
.)
mmap.write()
function now returns the number of bytes written like other write methods. (Contributed by Jakub Stasiak in
bpo-26335
.)
pkgutil.iter_modules()
and
pkgutil.walk_packages()
functions now return
ModuleInfo
named tuples. (Contributed by Ramchandra Apte in
bpo-17211
.)
re.sub()
now raises an error for invalid numerical group references in replacement templates even if the pattern is not found in the string. The error message for invalid group references now includes the group index and the position of the reference. (Contributed by SilentGhost, Serhiy Storchaka in
bpo-25953
.)
zipfile.ZipFile
will now raise
NotImplementedError
for unrecognized compression values. Previously a plain
RuntimeError
was raised. Additionally, calling
ZipFile
methods on a closed ZipFile or calling the
write()
method on a ZipFile created with mode
'r'
will raise a
ValueError
. Previously, a
RuntimeError
was raised in those scenarios.
when custom metaclasses are combined with zero-argument
super()
or direct references from methods to the implicit
__class__
closure variable, the implicit
__classcell__
namespace entry must now be passed up to
type.__new__
for initialisation. Failing to do so will result in a
DeprecationWarning
in Python 3.6 and a
RuntimeError
in Python 3.8.
PyMem_Malloc()
allocator family now uses the
pymalloc allocator
rather than the system
malloc()
. Applications calling
PyMem_Malloc()
without holding the GIL can now crash. Set the
PYTHONMALLOC
environment variable to
debug
to validate the
usage of memory allocators in your application. See
bpo-26249
.
Py_Exit()
(and the main interpreter) now override the exit status
with 120 if flushing buffered data failed. See
bpo-5319
.
There have been several major changes to the bytecode in Python 3.6.
FORMAT_VALUE
and
BUILD_STRING
opcodes as part
of the
格式化字符串文字
实现。
(Contributed by Eric Smith in
bpo-25483
and
Serhiy Storchaka in
bpo-27078
.)
BUILD_CONST_KEY_MAP
opcode to optimize the creation
of dictionaries with constant keys.
(Contributed by Serhiy Storchaka in
bpo-27140
.)
MAKE_FUNCTION
,
CALL_FUNCTION
,
CALL_FUNCTION_KW
and
BUILD_MAP_UNPACK_WITH_CALL
opcodes
have been modified, the new
CALL_FUNCTION_EX
and
BUILD_TUPLE_UNPACK_WITH_CALL
have been added, and
CALL_FUNCTION_VAR
,
CALL_FUNCTION_VAR_KW
and
MAKE_CLOSURE
opcodes
have been removed.
(Contributed by Demur Rumed in
bpo-27095
, and Serhiy Storchaka in
bpo-27213
,
bpo-28257
.)
SETUP_ANNOTATIONS
and
STORE_ANNOTATION
opcodes
have been added to support the new
variable annotation
句法。
(Contributed by Ivan Levkivskyi in
bpo-27985
.)
make
regen-all
build target
¶
To simplify cross-compilation, and to ensure that CPython can reliably be compiled without requiring an existing version of Python to already be available, the autotools-based build system no longer attempts to implicitly recompile generated files based on file modification times.
Instead, a new
make
regen-all
command has been added to force regeneration of these files when desired (e.g. after an initial version of Python has already been built based on the pregenerated versions).
More selective regeneration targets are also defined - see Makefile.pre.in 了解细节。
(Contributed by Victor Stinner in bpo-23404 .)
New in version 3.6.2.
make
touch
build target
¶
make
touch
build target previously used to request implicit regeneration of generated files by updating their modification times has been removed.
It has been replaced by the new
make
regen-all
target.
(Contributed by Victor Stinner in bpo-23404 .)
Changed in version 3.6.2.
PyExc_RecursionErrorInst
singleton that was part of the public API has been removed as its members being never cleared may cause a segfault during finalization of the interpreter. (Contributed by Xavier de Gaye in
bpo-22898
and
bpo-30697
.)
locale.localeconv()
function now sets temporarily the
LC_CTYPE
locale to the
LC_NUMERIC
locale in some cases. (Contributed by Victor Stinner in
bpo-31900
.)
xml.dom.minidom
and mod:
xml.sax
modules no longer process external entities by default. See also
bpo-17239
.
In 3.6.7 the
tokenize
module now implicitly emits a
NEWLINE
token when provided with input that does not have a trailing new line. This behavior now matches what the C tokenizer does internally. (Contributed by Ammar Askar in
bpo-33899
.)
dict
实现