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<H1><A NAME="SECTION0051500000000000000000">
3.15 <tt class="module">cPickle</tt> -- A faster <tt class="module">pickle</tt></A>
</H1>

<P>
<A NAME="module-cPickle"></A>

<P>
The <tt class="module">cPickle</tt> module supports serialization and
de-serialization of Python objects, providing an interface and
functionality nearly identical to the
<tt class="module"><a href="module-pickle.html">pickle</a></tt><a id='l2h-658' xml:id='l2h-658'></a> module.  There are several
differences, the most important being performance and subclassability.

<P>
First, <tt class="module">cPickle</tt> can be up to 1000 times faster than
<tt class="module">pickle</tt> because the former is implemented in C.  Second, in
the <tt class="module">cPickle</tt> module the callables <tt class="function">Pickler()</tt> and
<tt class="function">Unpickler()</tt> are functions, not classes.  This means that
you cannot use them to derive custom pickling and unpickling
subclasses.  Most applications have no need for this functionality and
should benefit from the greatly improved performance of the
<tt class="module">cPickle</tt> module.

<P>
The pickle data stream produced by <tt class="module">pickle</tt> and
<tt class="module">cPickle</tt> are identical, so it is possible to use
<tt class="module">pickle</tt> and <tt class="module">cPickle</tt> interchangeably with existing
pickles.<A NAME="tex2html23"
  HREF="#foot8958"><SUP>3.11</SUP></A>
<P>
There are additional minor differences in API between <tt class="module">cPickle</tt>
and <tt class="module">pickle</tt>, however for most applications, they are
interchangeable.  More documentation is provided in the
<tt class="module">pickle</tt> module documentation, which
includes a list of the documented differences.

<P>
<BR><HR><H4>Footnotes</H4>
<DL>
<DT><A NAME="foot8958">...
pickles.</A><A
 href="module-cPickle.html#tex2html23"><SUP>3.11</SUP></A></DT>
<DD>Since the pickle data format is actually a tiny
stack-oriented programming language, and some freedom is taken in the
encodings of certain objects, it is possible that the two modules
produce different data streams for the same input objects.  However it
is guaranteed that they will always be able to read each other's
data streams.

</DD>
</DL>
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	54
	55	<H1><A NAME="SECTION0051500000000000000000">
	56	3.15 <tt class="module">cPickle</tt> -- A faster <tt class="module">pickle</tt></A>
	57	</H1>
	58
	59	<P>
	60	<A NAME="module-cPickle"></A>
	61
	62	<P>
	63	The <tt class="module">cPickle</tt> module supports serialization and
	64	de-serialization of Python objects, providing an interface and
65	functionality nearly identical to the
66	<tt class="module"><a href="module-pickle.html">pickle</a></tt><a id='l2h-658' xml:id='l2h-658'></a> module. There are several
67	differences, the most important being performance and subclassability.
68
69	<P>
70	First, <tt class="module">cPickle</tt> can be up to 1000 times faster than
71	<tt class="module">pickle</tt> because the former is implemented in C. Second, in
72	the <tt class="module">cPickle</tt> module the callables <tt class="function">Pickler()</tt> and
73	<tt class="function">Unpickler()</tt> are functions, not classes. This means that
74	you cannot use them to derive custom pickling and unpickling
75	subclasses. Most applications have no need for this functionality and
76	should benefit from the greatly improved performance of the
77	<tt class="module">cPickle</tt> module.
78
79	<P>
80	The pickle data stream produced by <tt class="module">pickle</tt> and
81	<tt class="module">cPickle</tt> are identical, so it is possible to use
82	<tt class="module">pickle</tt> and <tt class="module">cPickle</tt> interchangeably with existing
83	pickles.<A NAME="tex2html23"
84	HREF="#foot8958"><SUP>3.11</SUP></A>
85	<P>
86	There are additional minor differences in API between <tt class="module">cPickle</tt>
87	and <tt class="module">pickle</tt>, however for most applications, they are
88	interchangeable. More documentation is provided in the
89	<tt class="module">pickle</tt> module documentation, which
90	includes a list of the documented differences.
91
92	<P>
93	<BR><HR><H4>Footnotes</H4>
94	<DL>
95	<DT><A NAME="foot8958">...
96	pickles.</A><A
97	href="module-cPickle.html#tex2html23"><SUP>3.11</SUP></A></DT>
98	<DD>Since the pickle data format is actually a tiny
99	stack-oriented programming language, and some freedom is taken in the
100	encodings of certain objects, it is possible that the two modules
101	produce different data streams for the same input objects. However it
102	is guaranteed that they will always be able to read each other's
103	data streams.
104
105	</DD>
106	</DL>
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