L_waveLength_iteration_线性波；波长_

#L_waveLength_iteration.py import math d = 0.45 g = 9.81 t = 1.0 block = g * t * t/(2 * 3.1415926) L = 1.0 for i in range(200): k = 2 * 3.14159265 / L L = block * math.tanh(k*d) print('kd =',k*d,'C = ',L/t,'L =',L,'k =',k,'w =',(L/t)*k) +++++++++++ Python News +++++++++++ What's New in Python 3.8.3 final? ================================= *Release date: 2020-05-13* Core and Builtins ----------------- - bpo-40527: Fix command line argument parsing: no longer write errors multiple times into stderr. - bpo-40417: Fix imp module deprecation warning when PyImport_ReloadModule is called. Patch by Robert Rouhani. - bpo-39562: The constant values of future flags in the :mod:`__future__` module are updated in order to prevent collision with compiler flags. Previously ``PyCF_ALLOW_TOP_LEVEL_AWAIT`` was clashing with ``CO_FUTURE_DIVISION``. Library ------- - bpo-40559: Fix possible memory leak in the C implementation of :class:`asyncio.Task`. - bpo-40355: Improve error reporting in :func:`ast.literal_eval` in the presence of malformed :class:`ast.Dict` nodes instead of silently ignoring any non-conforming elements. Patch by Curtis Bucher. - bpo-40459: :func:`platform.win32_ver` now produces correct *ptype* strings instead of empty strings. - bpo-40398: :func:`typing.get_args` now always returns an empty tuple for special generic aliases. Documentation ------------- - bpo-40561: Provide docstrings for webbrowser open functions. - bpo-39435: Fix an incorrect signature for :func:`pickle.loads` in the docs Windows ------- - bpo-40458: Increase reserved stack space to prevent overflow crash on Windows. C API ----- - bpo-40412: Nullify inittab_copy during finalization, preventing future interpreter initializations in an embedded situation from crashing. Patch by Gregory Szorc. What's New in Python 3.8.3 release candidate 1? =============================================== *Release date: 2020-04-29* Security -------- - bpo-40121: Fixes audit events raised on creating a new socket. - bpo-38576: Disallow control characters in hostnames in http.client, addressing CVE-2019-18348. Such potentially malicious header injection URLs now cause a InvalidURL to be raised. - bpo-39503: CVE-2020-8492: The :class:`~urllib.request.AbstractBasicAuthHandler` class of the :mod:`urllib.request` module uses an inefficient regular expression which can be exploited by an attacker to cause a denial of service. Fix the regex to prevent the catastrophic backtracking. Vulnerability reported by Ben Caller and Matt Schwager. Core and Builtins ----------------- - bpo-20526: Fix :c:func:`PyThreadState_Clear()`. ``PyThreadState.frame`` is a borrowed reference, not a strong reference: ``PyThreadState_Clear()`` must not call ``Py_CLEAR(tstate->frame)``. - bpo-39965: Correctly raise ``SyntaxError`` if *await* is used inside non-async functions and ``PyCF_ALLOW_TOP_LEVEL_AWAIT`` is set (like in the asyncio REPL). Patch by Pablo Galindo. - bpo-39562: Allow executing asynchronous comprehensions on the top level when the ``PyCF_ALLOW_TOP_LEVEL_AWAIT`` flag is given. Patch by Batuhan Taskaya. - bpo-38894: Fix a bug that was causing incomplete results when calling ``pathlib.Path.glob`` in the presence of symlinks that point to files where the user does not have read access. Patch by Pablo Galindo and Matt Wozniski. - bpo-39871: Fix a possible :exc:`SystemError` in ``math.{atan2,copysign,remainder}()`` when the first argument cannot be converted to a :class:`float`. Patch by Zachary Spytz. - bpo-39776: Fix race condition where threads created by PyGILState_Ensure() could get a duplicate id. This affects consumers of tstate->id like the contextvar caching machinery, which could return invalid cached objects under heavy thread load (observed in embedded scenarios). - bpo-39778: Fixed a crash due to incorrect handling of weak references in ``collections.OrderedDict`` classes. Patch by Pablo Galindo. - bpo-39520: Fix unparsing of ext slices with no items (``foo[:,]``). Patch by Batuhan Taskaya. - bpo-22490: Don't leak environment variable ``__PYVENV_LAUNCHER__`` into the interpreter session on macOS. Library ------- - bpo-40138: Fix the Windows implementation of :func:`os.waitpid` for exit code larger than ``INT_MAX >> 8``. The exit status is now interpreted as an unsigned number. - bpo-39942: Set "__main__" as the default module name when "__name__" is missing in :class:`typing.TypeVar`. Patch by Weipeng Hong. - bpo-40330: In :meth:`ShareableList.__setitem__`, check the size of a new string item after encoding it to utf-8, not before. - bpo-40287: Fixed ``SpooledTemporaryFile.seek()`` to return the position. - bpo-40260: Ensure :mod:`modulefinder` uses :func:`io.open_code` and respects coding comments. - bpo-40196: Fix a bug in the :mod:`symtable` module that was causing incorrectly report global variables as local. Patch by Pablo Galindo. - bpo-40126: Fixed reverting multiple patches in unittest.mock. Patcher's ``__exit__()`` is now never called if its ``__enter__()`` is failed. Returning true from ``__exit__()`` silences now the exception. - bpo-40089: Fix threading._after_fork(): if fork was not called by a thread spawned by threading.Thread, threading._after_fork() now creates a _MainThread instance for _main_thread, instead of a _DummyThread instance. - bpo-39503: :class:`~urllib.request.AbstractBasicAuthHandler` of :mod:`urllib.request` now parses all WWW-Authenticate HTTP headers and accepts multiple challenges per header: use the realm of the first Basic challenge. - bpo-40014: Fix ``os.getgrouplist()``: if ``getgrouplist()`` function fails because the group list is too small, retry with a larger group list. On failure, the glibc implementation of ``getgrouplist()`` sets ``ngroups`` to the total number of groups. For other implementations, double the group list size. - bpo-40016: In re docstring, clarify the relationship between inline and argument compile flags. - bpo-39953: Update internal table of OpenSSL error codes in the ``ssl`` module. - bpo-39360: Ensure all workers exit when finalizing a :class:`multiprocessing.Pool` implicitly via the module finalization handlers of multiprocessing. This fixes a deadlock situation that can be experienced when the Pool is not properly finalized via the context manager or a call to ``multiprocessing.Pool.terminate``. Patch by Batuhan Taskaya and Pablo Galindo. - bpo-39652: The column name found in ``sqlite3.Cursor.description`` is now truncated on the first '[' only if the PARSE_COLNAMES option is set. - bpo-39915: Ensure :attr:`unittest.mock.AsyncMock.await_args_list` has call objects in the order of awaited arguments instead of using :attr:`unittest.mock.Mock.call_args` which has the last value of the call. Patch by Karthikeyan Singaravelan. - bpo-38662: The ``ensurepip`` module now invokes ``pip`` via the ``runpy`` module. Hence it is no longer tightly coupled with the internal API of the bundled ``pip`` version, allowing easier updates to a newer ``pip`` version both internally and for distributors. - bpo-39916: More reliable use of ``os.scandir()`` in ``Path.glob()``. It no longer emits a ResourceWarning when interrupted. - bpo-39850: :mod:`multiprocessing` now supports abstract socket addresses (if abstract sockets are supported in the running platform). Patch by Pablo Galindo. - bpo-39828: Fix :mod:`json.tool` to catch :exc:`BrokenPipeError`. Patch by Dong-hee Na. - bpo-13487: Avoid a possible *"RuntimeError: dictionary changed size during iteration"* from :func:`inspect.getmodule` when it tried to loop through :attr:`sys.modules`.