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<title>pickletools — Tools for pickle developers &#8212; Python 3.7.4 documentation</title>
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<div class="section" id="module-pickletools">
<span id="pickletools-tools-for-pickle-developers"></span><h1><a class="reference internal" href="#module-pickletools" title="pickletools: Contains extensive comments about the pickle protocols and pickle-machine opcodes, as well as some useful functions."><code class="xref py py-mod docutils literal notranslate"><span class="pre">pickletools</span></code></a> — Tools for pickle developers<a class="headerlink" href="#module-pickletools" title="Permalink to this headline"></a></h1>
<p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.7/Lib/pickletools.py">Lib/pickletools.py</a></p>
<hr class="docutils" />
<p>This module contains various constants relating to the intimate details of the
<a class="reference internal" href="pickle.html#module-pickle" title="pickle: Convert Python objects to streams of bytes and back."><code class="xref py py-mod docutils literal notranslate"><span class="pre">pickle</span></code></a> module, some lengthy comments about the implementation, and a
few useful functions for analyzing pickled data. The contents of this module
are useful for Python core developers who are working on the <a class="reference internal" href="pickle.html#module-pickle" title="pickle: Convert Python objects to streams of bytes and back."><code class="xref py py-mod docutils literal notranslate"><span class="pre">pickle</span></code></a>;
ordinary users of the <a class="reference internal" href="pickle.html#module-pickle" title="pickle: Convert Python objects to streams of bytes and back."><code class="xref py py-mod docutils literal notranslate"><span class="pre">pickle</span></code></a> module probably won’t find the
<a class="reference internal" href="#module-pickletools" title="pickletools: Contains extensive comments about the pickle protocols and pickle-machine opcodes, as well as some useful functions."><code class="xref py py-mod docutils literal notranslate"><span class="pre">pickletools</span></code></a> module relevant.</p>
<div class="section" id="command-line-usage">
<h2>Command line usage<a class="headerlink" href="#command-line-usage" title="Permalink to this headline"></a></h2>
<div class="versionadded">
<p><span class="versionmodified added">New in version 3.2.</span></p>
</div>
<p>When invoked from the command line, <code class="docutils literal notranslate"><span class="pre">python</span> <span class="pre">-m</span> <span class="pre">pickletools</span></code> will
disassemble the contents of one or more pickle files. Note that if
you want to see the Python object stored in the pickle rather than the
details of pickle format, you may want to use <code class="docutils literal notranslate"><span class="pre">-m</span> <span class="pre">pickle</span></code> instead.
However, when the pickle file that you want to examine comes from an
untrusted source, <code class="docutils literal notranslate"><span class="pre">-m</span> <span class="pre">pickletools</span></code> is a safer option because it does
not execute pickle bytecode.</p>
<p>For example, with a tuple <code class="docutils literal notranslate"><span class="pre">(1,</span> <span class="pre">2)</span></code> pickled in file <code class="docutils literal notranslate"><span class="pre">x.pickle</span></code>:</p>
<div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$</span> python -m pickle x.pickle
<span class="go">(1, 2)</span>
<span class="gp">$</span> python -m pickletools x.pickle
<span class="go"> 0: \x80 PROTO 3</span>
<span class="go"> 2: K BININT1 1</span>
<span class="go"> 4: K BININT1 2</span>
<span class="go"> 6: \x86 TUPLE2</span>
<span class="go"> 7: q BINPUT 0</span>
<span class="go"> 9: . STOP</span>
<span class="go">highest protocol among opcodes = 2</span>
</pre></div>
</div>
<div class="section" id="command-line-options">
<h3>Command line options<a class="headerlink" href="#command-line-options" title="Permalink to this headline"></a></h3>
<dl class="cmdoption">
<dt id="cmdoption-pickletools-a">
<code class="descname">-a</code><code class="descclassname"></code><code class="descclassname">, </code><code class="descname">--annotate</code><code class="descclassname"></code><a class="headerlink" href="#cmdoption-pickletools-a" title="Permalink to this definition"></a></dt>
<dd><p>Annotate each line with a short opcode description.</p>
</dd></dl>
<dl class="cmdoption">
<dt id="cmdoption-pickletools-o">
<code class="descname">-o</code><code class="descclassname"></code><code class="descclassname">, </code><code class="descname">--output</code><code class="descclassname">=&lt;file&gt;</code><a class="headerlink" href="#cmdoption-pickletools-o" title="Permalink to this definition"></a></dt>
<dd><p>Name of a file where the output should be written.</p>
</dd></dl>
<dl class="cmdoption">
<dt id="cmdoption-pickletools-l">
<code class="descname">-l</code><code class="descclassname"></code><code class="descclassname">, </code><code class="descname">--indentlevel</code><code class="descclassname">=&lt;num&gt;</code><a class="headerlink" href="#cmdoption-pickletools-l" title="Permalink to this definition"></a></dt>
<dd><p>The number of blanks by which to indent a new MARK level.</p>
</dd></dl>
<dl class="cmdoption">
<dt id="cmdoption-pickletools-m">
<code class="descname">-m</code><code class="descclassname"></code><code class="descclassname">, </code><code class="descname">--memo</code><code class="descclassname"></code><a class="headerlink" href="#cmdoption-pickletools-m" title="Permalink to this definition"></a></dt>
<dd><p>When multiple objects are disassembled, preserve memo between
disassemblies.</p>
</dd></dl>
<dl class="cmdoption">
<dt id="cmdoption-pickletools-p">
<code class="descname">-p</code><code class="descclassname"></code><code class="descclassname">, </code><code class="descname">--preamble</code><code class="descclassname">=&lt;preamble&gt;</code><a class="headerlink" href="#cmdoption-pickletools-p" title="Permalink to this definition"></a></dt>
<dd><p>When more than one pickle file are specified, print given preamble
before each disassembly.</p>
</dd></dl>
</div>
</div>
<div class="section" id="programmatic-interface">
<h2>Programmatic Interface<a class="headerlink" href="#programmatic-interface" title="Permalink to this headline"></a></h2>
<dl class="function">
<dt id="pickletools.dis">
<code class="descclassname">pickletools.</code><code class="descname">dis</code><span class="sig-paren">(</span><em>pickle</em>, <em>out=None</em>, <em>memo=None</em>, <em>indentlevel=4</em>, <em>annotate=0</em><span class="sig-paren">)</span><a class="headerlink" href="#pickletools.dis" title="Permalink to this definition"></a></dt>
<dd><p>Outputs a symbolic disassembly of the pickle to the file-like
object <em>out</em>, defaulting to <code class="docutils literal notranslate"><span class="pre">sys.stdout</span></code>. <em>pickle</em> can be a
string or a file-like object. <em>memo</em> can be a Python dictionary
that will be used as the pickle’s memo; it can be used to perform
disassemblies across multiple pickles created by the same
pickler. Successive levels, indicated by <code class="docutils literal notranslate"><span class="pre">MARK</span></code> opcodes in the
stream, are indented by <em>indentlevel</em> spaces. If a nonzero value
is given to <em>annotate</em>, each opcode in the output is annotated with
a short description. The value of <em>annotate</em> is used as a hint for
the column where annotation should start.</p>
<div class="versionadded">
<p><span class="versionmodified added">New in version 3.2: </span>The <em>annotate</em> argument.</p>
</div>
</dd></dl>
<dl class="function">
<dt id="pickletools.genops">
<code class="descclassname">pickletools.</code><code class="descname">genops</code><span class="sig-paren">(</span><em>pickle</em><span class="sig-paren">)</span><a class="headerlink" href="#pickletools.genops" title="Permalink to this definition"></a></dt>
<dd><p>Provides an <a class="reference internal" href="../glossary.html#term-iterator"><span class="xref std std-term">iterator</span></a> over all of the opcodes in a pickle, returning a
sequence of <code class="docutils literal notranslate"><span class="pre">(opcode,</span> <span class="pre">arg,</span> <span class="pre">pos)</span></code> triples. <em>opcode</em> is an instance of an
<code class="xref py py-class docutils literal notranslate"><span class="pre">OpcodeInfo</span></code> class; <em>arg</em> is the decoded value, as a Python object, of
the opcode’s argument; <em>pos</em> is the position at which this opcode is located.
<em>pickle</em> can be a string or a file-like object.</p>
</dd></dl>
<dl class="function">
<dt id="pickletools.optimize">
<code class="descclassname">pickletools.</code><code class="descname">optimize</code><span class="sig-paren">(</span><em>picklestring</em><span class="sig-paren">)</span><a class="headerlink" href="#pickletools.optimize" title="Permalink to this definition"></a></dt>
<dd><p>Returns a new equivalent pickle string after eliminating unused <code class="docutils literal notranslate"><span class="pre">PUT</span></code>
opcodes. The optimized pickle is shorter, takes less transmission time,
requires less storage space, and unpickles more efficiently.</p>
</dd></dl>
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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">pickletools</span></code> — Tools for pickle developers</a><ul>
<li><a class="reference internal" href="#command-line-usage">Command line usage</a><ul>
<li><a class="reference internal" href="#command-line-options">Command line options</a></li>
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<li><a class="reference internal" href="#programmatic-interface">Programmatic Interface</a></li>
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