**************************** What's New In Python 3.6 **************************** :Release: |release| :Date: |today| .. Rules for maintenance: * Anyone can add text to this document. Do not spend very much time on the wording of your changes, because your text will probably get rewritten to some degree. * The maintainer will go through Misc/NEWS periodically and add changes; it's therefore more important to add your changes to Misc/NEWS than to this file. * This is not a complete list of every single change; completeness is the purpose of Misc/NEWS. Some changes I consider too small or esoteric to include. If such a change is added to the text, I'll just remove it. (This is another reason you shouldn't spend too much time on writing your addition.) * If you want to draw your new text to the attention of the maintainer, add 'XXX' to the beginning of the paragraph or section. * It's OK to just add a fragmentary note about a change. For example: "XXX Describe the transmogrify() function added to the socket module." The maintainer will research the change and write the necessary text. * You can comment out your additions if you like, but it's not necessary (especially when a final release is some months away). * Credit the author of a patch or bugfix. Just the name is sufficient; the e-mail address isn't necessary. * It's helpful to add the bug/patch number as a comment: XXX Describe the transmogrify() function added to the socket module. (Contributed by P.Y. Developer in :issue:`12345`.) This saves the maintainer the effort of going through the Mercurial log when researching a change. This article explains the new features in Python 3.6, compared to 3.5. For full details, see the :source:`Misc/NEWS` file. .. note:: Prerelease users should be aware that this document is currently in draft form. It will be updated substantially as Python 3.6 moves towards release, so it's worth checking back even after reading earlier versions. Summary -- Release highlights ============================= .. This section singles out the most important changes in Python 3.6. Brevity is key. * None yet. .. PEP-sized items next. .. _pep-4XX: .. PEP 4XX: Virtual Environments .. ============================= .. (Implemented by Foo Bar.) .. .. seealso:: :pep:`4XX` - Python Virtual Environments PEP written by Carl Meyer Other Language Changes ====================== * None yet. New Modules =========== * None yet. Improved Modules ================ datetime -------- :meth:`datetime.strftime ` and :meth:`date.strftime ` methods now support ISO 8601 date directives ``%G``, ``%u`` and ``%V``. (Contributed by Ashley Anderson in :issue:`12006`.) pickle ------ Objects that need calling ``__new__`` with keyword arguments, can now be pickled using :ref:`pickle protocols ` older than protocol version 4. Protocol version 4 already supports this case. (Contributed by Serhiy Storchaka in :issue:`24164`.) rlcomplete ---------- Private and special attribute names now are omitted unless the prefix starts with underscores. A space or a colon can be added after completed keyword. (Contributed by Serhiy Storchaka in :issue:`25011` and :issue:`25209`.) urllib.robotparser ------------------ :class:`~urllib.robotparser.RobotFileParser` now supports ``Crawl-delay`` and ``Request-rate`` extensions. (Contributed by Nikolay Bogoychev in :issue:`16099`.) Optimizations ============= * The ASCII decoder is now up to 60 times as fast for error handlers: ``surrogateescape``, ``ignore`` and ``replace`` (Contributed by Victor Stinner in :issue:`24870`). * The ASCII and the Latin1 encoders are now up to 3 times as fast for the error ``surrogateescape`` (Contributed by Victor Stinner in :issue:`25227`). * The UTF-8 encoder is now up to 75 times as fast for error handlers: ``ignore``, ``replace``, ``surrogateescape``, ``surrogatepass`` (Contributed by Victor Stinner in :issue:`25267`). * The UTF-8 decoder is now up to 15 times as fast for error handlers: ``ignore``, ``replace`` and ``surrogateescape`` (Contributed by Victor Stinner in :issue:`25301`). * ``bytes % args`` is now up to 2 times faster. (Contributed by Victor Stinner in :issue:`25349`). * ``bytearray % args`` is now between 2.5 and 5 times faster. (Contributed by Victor Stinner in :issue:`25399`). * Optimize :meth:`bytes.fromhex` and :meth:`bytearray.fromhex`: they are now between 2x and 3.5x faster. (Contributed by Victor Stinner in :issue:`25401`). Build and C API Changes ======================= * None yet. Deprecated ========== New Keywords ------------ ``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. Deprecated Python modules, functions and methods ------------------------------------------------ * None yet. Deprecated functions and types of the C API ------------------------------------------- * None yet. Deprecated features ------------------- * The ``pyvenv`` script has been deprecated in favour of ``python3 -m venv``. This prevents confusion as to what Python interpreter ``pyvenv`` is connected to and thus what Python interpreter will be used by the virtual environment. See :issue:`25154`. Removed ======= API and Feature Removals ------------------------ * ``inspect.getargspec()`` was removed (was deprecated since CPython 3.0). :func:`inspect.getfullargspec` is an almost drop in replacement. * ``inspect.getmoduleinfo()`` was removed (was deprecated since CPython 3.3). :func:`inspect.getmodulename` should be used for obtaining the module name for a given path. Porting to Python 3.6 ===================== This section lists previously described changes and other bugfixes that may require changes to your code. Changes in the Python API ------------------------- * Reading the :attr:`~urllib.parse.SplitResult.port` attribute of :func:`urllib.parse.urlsplit` and :func:`~urllib.parse.urlparse` results now raises :exc:`ValueError` for out-of-range values, rather than returning :const:`None`. See :issue:`20059`. * The :mod:`imp` module now raises a :exc:`DeprecationWarning` instead of :exc:`PendingDeprecationWarning`. Changes in the C API -------------------- * None yet.