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<section id="iterator-objects">
<span id="id1"></span><h1>Iterator Objects<a class="headerlink" href="#iterator-objects" title="Permalink to this headline">¶</a></h1>
<p>Python provides two general-purpose iterator objects. The first, a sequence
iterator, works with an arbitrary sequence supporting the <code class="xref py py-meth docutils literal notranslate"><span class="pre">__getitem__()</span></code>
method. The second works with a callable object and a sentinel value, calling
the callable for each item in the sequence, and ending the iteration when the
sentinel value is returned.</p>
<dl class="c var">
<dt class="sig sig-object c" id="c.PySeqIter_Type">
<a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PySeqIter_Type</span></span></span><a class="headerlink" href="#c.PySeqIter_Type" title="Permalink to this definition">¶</a><br /></dt>
<dd><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><p>Type object for iterator objects returned by <a class="reference internal" href="#c.PySeqIter_New" title="PySeqIter_New"><code class="xref c c-func docutils literal notranslate"><span class="pre">PySeqIter_New()</span></code></a> and the
one-argument form of the <a class="reference internal" href="../library/functions.html#iter" title="iter"><code class="xref py py-func docutils literal notranslate"><span class="pre">iter()</span></code></a> built-in function for built-in sequence
types.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PySeqIter_Check">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PySeqIter_Check</span></span></span><span class="sig-paren">(</span><span class="n"><span class="pre">op</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PySeqIter_Check" title="Permalink to this definition">¶</a><br /></dt>
<dd><p>Return true if the type of <em>op</em> is <a class="reference internal" href="#c.PySeqIter_Type" title="PySeqIter_Type"><code class="xref c c-data docutils literal notranslate"><span class="pre">PySeqIter_Type</span></code></a>. This function
always succeeds.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PySeqIter_New">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PySeqIter_New</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">seq</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PySeqIter_New" title="Permalink to this definition">¶</a><br /></dt>
<dd><em class="refcount">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><p>Return an iterator that works with a general sequence object, <em>seq</em>. The
iteration ends when the sequence raises <a class="reference internal" href="../library/exceptions.html#IndexError" title="IndexError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">IndexError</span></code></a> for the subscripting
operation.</p>
</dd></dl>
<dl class="c var">
<dt class="sig sig-object c" id="c.PyCallIter_Type">
<a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyCallIter_Type</span></span></span><a class="headerlink" href="#c.PyCallIter_Type" title="Permalink to this definition">¶</a><br /></dt>
<dd><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><p>Type object for iterator objects returned by <a class="reference internal" href="#c.PyCallIter_New" title="PyCallIter_New"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyCallIter_New()</span></code></a> and the
two-argument form of the <a class="reference internal" href="../library/functions.html#iter" title="iter"><code class="xref py py-func docutils literal notranslate"><span class="pre">iter()</span></code></a> built-in function.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyCallIter_Check">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyCallIter_Check</span></span></span><span class="sig-paren">(</span><span class="n"><span class="pre">op</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyCallIter_Check" title="Permalink to this definition">¶</a><br /></dt>
<dd><p>Return true if the type of <em>op</em> is <a class="reference internal" href="#c.PyCallIter_Type" title="PyCallIter_Type"><code class="xref c c-data docutils literal notranslate"><span class="pre">PyCallIter_Type</span></code></a>. This
function always succeeds.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyCallIter_New">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyCallIter_New</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">callable</span></span>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">sentinel</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyCallIter_New" title="Permalink to this definition">¶</a><br /></dt>
<dd><em class="refcount">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><p>Return a new iterator. The first parameter, <em>callable</em>, can be any Python
callable object that can be called with no parameters; each call to it should
return the next item in the iteration. When <em>callable</em> returns a value equal to
<em>sentinel</em>, the iteration will be terminated.</p>
</dd></dl>
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