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<div class="section" id="module-whoosh.idsets">
<span id="support-bitvector-module"></span><h1><tt class="docutils literal"><span class="pre">support.bitvector</span></tt> module<a class="headerlink" href="#module-whoosh.idsets" title="Permalink to this headline">¶</a></h1>
<p>An implementation of an object that acts like a collection of on/off bits.</p>
<div class="section" id="base-classes">
<h2>Base classes<a class="headerlink" href="#base-classes" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="whoosh.idsets.DocIdSet">
<em class="property">class </em><tt class="descclassname">whoosh.idsets.</tt><tt class="descname">DocIdSet</tt><a class="headerlink" href="#whoosh.idsets.DocIdSet" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for a set of positive integers, implementing a subset of the
built-in <tt class="docutils literal"><span class="pre">set</span></tt> type’s interface with extra docid-related methods.</p>
<p>This is a superclass for alternative set implementations to the built-in
<tt class="docutils literal"><span class="pre">set</span></tt> which are more memory-efficient and specialized toward storing
sorted lists of positive integers, though they will inevitably be slower
than <tt class="docutils literal"><span class="pre">set</span></tt> for most operations since they’re pure Python.</p>
<dl class="method">
<dt id="whoosh.idsets.DocIdSet.after">
<tt class="descname">after</tt><big>(</big><big>)</big><a class="headerlink" href="#whoosh.idsets.DocIdSet.after" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns the next integer in the set after <tt class="docutils literal"><span class="pre">i</span></tt>, or None.</p>
</dd></dl>
<dl class="method">
<dt id="whoosh.idsets.DocIdSet.before">
<tt class="descname">before</tt><big>(</big><big>)</big><a class="headerlink" href="#whoosh.idsets.DocIdSet.before" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns the previous integer in the set before <tt class="docutils literal"><span class="pre">i</span></tt>, or None.</p>
</dd></dl>
<dl class="method">
<dt id="whoosh.idsets.DocIdSet.first">
<tt class="descname">first</tt><big>(</big><big>)</big><a class="headerlink" href="#whoosh.idsets.DocIdSet.first" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns the first (lowest) integer in the set.</p>
</dd></dl>
<dl class="method">
<dt id="whoosh.idsets.DocIdSet.invert_update">
<tt class="descname">invert_update</tt><big>(</big><em>size</em><big>)</big><a class="headerlink" href="#whoosh.idsets.DocIdSet.invert_update" title="Permalink to this definition">¶</a></dt>
<dd><p>Updates the set in-place to contain numbers in the range
<tt class="docutils literal"><span class="pre">[0</span> <span class="pre">-</span> <span class="pre">size)</span></tt> except numbers that are in this set.</p>
</dd></dl>
<dl class="method">
<dt id="whoosh.idsets.DocIdSet.last">
<tt class="descname">last</tt><big>(</big><big>)</big><a class="headerlink" href="#whoosh.idsets.DocIdSet.last" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns the last (highest) integer in the set.</p>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="whoosh.idsets.BaseBitSet">
<em class="property">class </em><tt class="descclassname">whoosh.idsets.</tt><tt class="descname">BaseBitSet</tt><a class="headerlink" href="#whoosh.idsets.BaseBitSet" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</div>
<div class="section" id="implementation-classes">
<h2>Implementation classes<a class="headerlink" href="#implementation-classes" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="whoosh.idsets.BitSet">
<em class="property">class </em><tt class="descclassname">whoosh.idsets.</tt><tt class="descname">BitSet</tt><big>(</big><em>source=None</em>, <em>size=0</em><big>)</big><a class="headerlink" href="#whoosh.idsets.BitSet" title="Permalink to this definition">¶</a></dt>
<dd><p>A DocIdSet backed by an array of bits. This can also be useful as a bit
array (e.g. for a Bloom filter). It is much more memory efficient than a
large built-in set of integers, but wastes memory for sparse sets.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>maxsize</strong> – the maximum size of the bit array.</li>
<li><strong>source</strong> – an iterable of positive integers to add to this set.</li>
<li><strong>bits</strong> – an array of unsigned bytes (“B”) to use as the underlying
bit array. This is used by some of the object’s methods.</li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="class">
<dt id="whoosh.idsets.OnDiskBitSet">
<em class="property">class </em><tt class="descclassname">whoosh.idsets.</tt><tt class="descname">OnDiskBitSet</tt><big>(</big><em>dbfile</em>, <em>basepos</em>, <em>bytecount</em><big>)</big><a class="headerlink" href="#whoosh.idsets.OnDiskBitSet" title="Permalink to this definition">¶</a></dt>
<dd><p>A DocIdSet backed by an array of bits on disk.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">st</span> <span class="o">=</span> <span class="n">RamStorage</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">f</span> <span class="o">=</span> <span class="n">st</span><span class="o">.</span><span class="n">create_file</span><span class="p">(</span><span class="s">"test.bin"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">bs</span> <span class="o">=</span> <span class="n">BitSet</span><span class="p">([</span><span class="mi">1</span><span class="p">,</span> <span class="mi">10</span><span class="p">,</span> <span class="mi">15</span><span class="p">,</span> <span class="mi">7</span><span class="p">,</span> <span class="mi">2</span><span class="p">])</span>
<span class="gp">>>> </span><span class="n">bytecount</span> <span class="o">=</span> <span class="n">bs</span><span class="o">.</span><span class="n">to_disk</span><span class="p">(</span><span class="n">f</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">f</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="gp">>>> </span><span class="c"># ...</span>
<span class="gp">>>> </span><span class="n">f</span> <span class="o">=</span> <span class="n">st</span><span class="o">.</span><span class="n">open_file</span><span class="p">(</span><span class="s">"test.bin"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">odbs</span> <span class="o">=</span> <span class="n">OnDiskBitSet</span><span class="p">(</span><span class="n">f</span><span class="p">,</span> <span class="n">bytecount</span><span class="p">)</span>
<span class="gp">>>> </span><span class="nb">list</span><span class="p">(</span><span class="n">odbs</span><span class="p">)</span>
<span class="go">[1, 2, 7, 10, 15]</span>
</pre></div>
</div>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>dbfile</strong> – a <a class="reference internal" href="filedb/structfile.html#whoosh.filedb.structfile.StructFile" title="whoosh.filedb.structfile.StructFile"><tt class="xref py py-class docutils literal"><span class="pre">StructFile</span></tt></a> object
to read from.</li>
<li><strong>basepos</strong> – the base position of the bytes in the given file.</li>
<li><strong>bytecount</strong> – the number of bytes to use for the bit array.</li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="class">
<dt id="whoosh.idsets.SortedIntSet">
<em class="property">class </em><tt class="descclassname">whoosh.idsets.</tt><tt class="descname">SortedIntSet</tt><big>(</big><em>source=None</em><big>)</big><a class="headerlink" href="#whoosh.idsets.SortedIntSet" title="Permalink to this definition">¶</a></dt>
<dd><p>A DocIdSet backed by a sorted array of integers.</p>
</dd></dl>
<dl class="class">
<dt id="whoosh.idsets.MultiIdSet">
<em class="property">class </em><tt class="descclassname">whoosh.idsets.</tt><tt class="descname">MultiIdSet</tt><big>(</big><em>idsets</em>, <em>offsets</em><big>)</big><a class="headerlink" href="#whoosh.idsets.MultiIdSet" title="Permalink to this definition">¶</a></dt>
<dd><p>Wraps multiple SERIAL sub-DocIdSet objects and presents them as an
aggregated, read-only set.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>idsets</strong> – a list of DocIdSet objects.</li>
<li><strong>offsets</strong> – a list of offsets corresponding to the DocIdSet objects
in <tt class="docutils literal"><span class="pre">idsets</span></tt>.</li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
</div>
</div>
</div>
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<ul>
<li><a class="reference internal" href="#"><tt class="docutils literal"><span class="pre">support.bitvector</span></tt> module</a><ul>
<li><a class="reference internal" href="#base-classes">Base classes</a></li>
<li><a class="reference internal" href="#implementation-classes">Implementation classes</a></li>
</ul>
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