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| author | Antoine Pitrou <solipsis@pitrou.net> | 2013-12-07 00:05:57 (GMT) |
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| committer | Antoine Pitrou <solipsis@pitrou.net> | 2013-12-07 00:05:57 (GMT) |
| commit | 9bcb1127f1d1305cc8071f8b4460af3b34f3ec74 (patch) | |
| tree | d53c9eaa705cc16d0651aa5af6517982f374f753 /Doc | |
| parent | 9858e8b98db6c8997abccb8b7878f59547f31d08 (diff) | |
| download | cpython-9bcb1127f1d1305cc8071f8b4460af3b34f3ec74.zip cpython-9bcb1127f1d1305cc8071f8b4460af3b34f3ec74.tar.gz cpython-9bcb1127f1d1305cc8071f8b4460af3b34f3ec74.tar.bz2 | |
Mention pickle protocol 4, and some tweaks.
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/library/pickle.rst | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/Doc/library/pickle.rst b/Doc/library/pickle.rst index cfd5f79..1f35b60 100644 --- a/Doc/library/pickle.rst +++ b/Doc/library/pickle.rst @@ -94,6 +94,9 @@ There are fundamental differences between the pickle protocols and The :mod:`json` module: a standard library module allowing JSON serialization and deserialization. + +.. _pickle-protocols: + Data stream format ------------------ @@ -125,10 +128,15 @@ There are currently 4 different protocols which can be used for pickling. efficient pickling of :term:`new-style class`\es. Refer to :pep:`307` for information about improvements brought by protocol 2. -* Protocol version 3 was added in Python 3. It has explicit support for +* Protocol version 3 was added in Python 3.0. It has explicit support for :class:`bytes` objects and cannot be unpickled by Python 2.x. This is - the default as well as the current recommended protocol; use it whenever - possible. + the default protocol, and the recommended protocol when compatibility with + other Python 3 versions is required. + +* Protocol version 4 was added in Python 3.4. It adds support for very large + objects, pickling more kinds of objects, and some data format + optimizations. Refer to :pep:`3154` for information about improvements + brought by protocol 4. .. note:: Serialization is a more primitive notion than persistence; although @@ -156,13 +164,16 @@ The :mod:`pickle` module provides the following constants: .. data:: HIGHEST_PROTOCOL - The highest protocol version available. This value can be passed as a - *protocol* value. + An integer, the highest :ref:`protocol version <pickle-protocols>` + available. This value can be passed as a *protocol* value to functions + :func:`dump` and :func:`dumps` as well as the :class:`Pickler` + constructor. .. data:: DEFAULT_PROTOCOL - The default protocol used for pickling. May be less than HIGHEST_PROTOCOL. - Currently the default protocol is 3, a new protocol designed for Python 3.0. + An integer, the default :ref:`protocol version <pickle-protocols>` used + for pickling. May be less than :data:`HIGHEST_PROTOCOL`. Currently the + default protocol is 3, a new protocol designed for Python 3.0. The :mod:`pickle` module provides the following functions to make the pickling |