225 lines
10 KiB
HTML
225 lines
10 KiB
HTML
|
||
<!DOCTYPE html>
|
||
|
||
<html xmlns="http://www.w3.org/1999/xhtml">
|
||
<head>
|
||
<meta charset="utf-8" />
|
||
<title>Iterator Protocol — Python 3.7.4 documentation</title>
|
||
<link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" />
|
||
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
|
||
|
||
<script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script>
|
||
<script type="text/javascript" src="../_static/jquery.js"></script>
|
||
<script type="text/javascript" src="../_static/underscore.js"></script>
|
||
<script type="text/javascript" src="../_static/doctools.js"></script>
|
||
<script type="text/javascript" src="../_static/language_data.js"></script>
|
||
|
||
<script type="text/javascript" src="../_static/sidebar.js"></script>
|
||
|
||
<link rel="search" type="application/opensearchdescription+xml"
|
||
title="Search within Python 3.7.4 documentation"
|
||
href="../_static/opensearch.xml"/>
|
||
<link rel="author" title="About these documents" href="../about.html" />
|
||
<link rel="index" title="Index" href="../genindex.html" />
|
||
<link rel="search" title="Search" href="../search.html" />
|
||
<link rel="copyright" title="Copyright" href="../copyright.html" />
|
||
<link rel="next" title="Buffer Protocol" href="buffer.html" />
|
||
<link rel="prev" title="Mapping Protocol" href="mapping.html" />
|
||
<link rel="shortcut icon" type="image/png" href="../_static/py.png" />
|
||
<link rel="canonical" href="https://docs.python.org/3/c-api/iter.html" />
|
||
|
||
<script type="text/javascript" src="../_static/copybutton.js"></script>
|
||
<script type="text/javascript" src="../_static/switchers.js"></script>
|
||
|
||
|
||
|
||
<style>
|
||
@media only screen {
|
||
table.full-width-table {
|
||
width: 100%;
|
||
}
|
||
}
|
||
</style>
|
||
|
||
|
||
</head><body>
|
||
|
||
<div class="related" role="navigation" aria-label="related navigation">
|
||
<h3>Navigation</h3>
|
||
<ul>
|
||
<li class="right" style="margin-right: 10px">
|
||
<a href="../genindex.html" title="General Index"
|
||
accesskey="I">index</a></li>
|
||
<li class="right" >
|
||
<a href="../py-modindex.html" title="Python Module Index"
|
||
>modules</a> |</li>
|
||
<li class="right" >
|
||
<a href="buffer.html" title="Buffer Protocol"
|
||
accesskey="N">next</a> |</li>
|
||
<li class="right" >
|
||
<a href="mapping.html" title="Mapping Protocol"
|
||
accesskey="P">previous</a> |</li>
|
||
<li><img src="../_static/py.png" alt=""
|
||
style="vertical-align: middle; margin-top: -1px"/></li>
|
||
<li><a href="https://www.python.org/">Python</a> »</li>
|
||
<li>
|
||
<span class="language_switcher_placeholder">en</span>
|
||
<span class="version_switcher_placeholder">3.7.4</span>
|
||
<a href="../index.html">Documentation </a> »
|
||
</li>
|
||
|
||
<li class="nav-item nav-item-1"><a href="index.html" >Python/C API Reference Manual</a> »</li>
|
||
<li class="nav-item nav-item-2"><a href="abstract.html" accesskey="U">Abstract Objects Layer</a> »</li>
|
||
<li class="right">
|
||
|
||
|
||
<div class="inline-search" style="display: none" role="search">
|
||
<form class="inline-search" action="../search.html" method="get">
|
||
<input placeholder="Quick search" type="text" name="q" />
|
||
<input type="submit" value="Go" />
|
||
<input type="hidden" name="check_keywords" value="yes" />
|
||
<input type="hidden" name="area" value="default" />
|
||
</form>
|
||
</div>
|
||
<script type="text/javascript">$('.inline-search').show(0);</script>
|
||
|
|
||
</li>
|
||
|
||
</ul>
|
||
</div>
|
||
|
||
<div class="document">
|
||
<div class="documentwrapper">
|
||
<div class="bodywrapper">
|
||
<div class="body" role="main">
|
||
|
||
<div class="section" id="iterator-protocol">
|
||
<span id="iterator"></span><h1>Iterator Protocol<a class="headerlink" href="#iterator-protocol" title="Permalink to this headline">¶</a></h1>
|
||
<p>There are two functions specifically for working with iterators.</p>
|
||
<dl class="function">
|
||
<dt id="c.PyIter_Check">
|
||
int <code class="descname">PyIter_Check</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyIter_Check" title="Permalink to this definition">¶</a></dt>
|
||
<dd><p>Return true if the object <em>o</em> supports the iterator protocol.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="function">
|
||
<dt id="c.PyIter_Next">
|
||
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyIter_Next</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyIter_Next" title="Permalink to this definition">¶</a></dt>
|
||
<dd><em class="refcount">Return value: New reference.</em><p>Return the next value from the iteration <em>o</em>. The object must be an iterator
|
||
(it is up to the caller to check this). If there are no remaining values,
|
||
returns <em>NULL</em> with no exception set. If an error occurs while retrieving
|
||
the item, returns <em>NULL</em> and passes along the exception.</p>
|
||
</dd></dl>
|
||
|
||
<p>To write a loop which iterates over an iterator, the C code should look
|
||
something like this:</p>
|
||
<div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="n">PyObject</span> <span class="o">*</span><span class="n">iterator</span> <span class="o">=</span> <span class="n">PyObject_GetIter</span><span class="p">(</span><span class="n">obj</span><span class="p">);</span>
|
||
<span class="n">PyObject</span> <span class="o">*</span><span class="n">item</span><span class="p">;</span>
|
||
|
||
<span class="k">if</span> <span class="p">(</span><span class="n">iterator</span> <span class="o">==</span> <span class="nb">NULL</span><span class="p">)</span> <span class="p">{</span>
|
||
<span class="cm">/* propagate error */</span>
|
||
<span class="p">}</span>
|
||
|
||
<span class="k">while</span> <span class="p">(</span><span class="n">item</span> <span class="o">=</span> <span class="n">PyIter_Next</span><span class="p">(</span><span class="n">iterator</span><span class="p">))</span> <span class="p">{</span>
|
||
<span class="cm">/* do something with item */</span>
|
||
<span class="p">...</span>
|
||
<span class="cm">/* release reference when done */</span>
|
||
<span class="n">Py_DECREF</span><span class="p">(</span><span class="n">item</span><span class="p">);</span>
|
||
<span class="p">}</span>
|
||
|
||
<span class="n">Py_DECREF</span><span class="p">(</span><span class="n">iterator</span><span class="p">);</span>
|
||
|
||
<span class="k">if</span> <span class="p">(</span><span class="n">PyErr_Occurred</span><span class="p">())</span> <span class="p">{</span>
|
||
<span class="cm">/* propagate error */</span>
|
||
<span class="p">}</span>
|
||
<span class="k">else</span> <span class="p">{</span>
|
||
<span class="cm">/* continue doing useful work */</span>
|
||
<span class="p">}</span>
|
||
</pre></div>
|
||
</div>
|
||
</div>
|
||
|
||
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
|
||
<div class="sphinxsidebarwrapper">
|
||
<h4>Previous topic</h4>
|
||
<p class="topless"><a href="mapping.html"
|
||
title="previous chapter">Mapping Protocol</a></p>
|
||
<h4>Next topic</h4>
|
||
<p class="topless"><a href="buffer.html"
|
||
title="next chapter">Buffer Protocol</a></p>
|
||
<div role="note" aria-label="source link">
|
||
<h3>This Page</h3>
|
||
<ul class="this-page-menu">
|
||
<li><a href="../bugs.html">Report a Bug</a></li>
|
||
<li>
|
||
<a href="https://github.com/python/cpython/blob/3.7/Doc/c-api/iter.rst"
|
||
rel="nofollow">Show Source
|
||
</a>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="clearer"></div>
|
||
</div>
|
||
<div class="related" role="navigation" aria-label="related navigation">
|
||
<h3>Navigation</h3>
|
||
<ul>
|
||
<li class="right" style="margin-right: 10px">
|
||
<a href="../genindex.html" title="General Index"
|
||
>index</a></li>
|
||
<li class="right" >
|
||
<a href="../py-modindex.html" title="Python Module Index"
|
||
>modules</a> |</li>
|
||
<li class="right" >
|
||
<a href="buffer.html" title="Buffer Protocol"
|
||
>next</a> |</li>
|
||
<li class="right" >
|
||
<a href="mapping.html" title="Mapping Protocol"
|
||
>previous</a> |</li>
|
||
<li><img src="../_static/py.png" alt=""
|
||
style="vertical-align: middle; margin-top: -1px"/></li>
|
||
<li><a href="https://www.python.org/">Python</a> »</li>
|
||
<li>
|
||
<span class="language_switcher_placeholder">en</span>
|
||
<span class="version_switcher_placeholder">3.7.4</span>
|
||
<a href="../index.html">Documentation </a> »
|
||
</li>
|
||
|
||
<li class="nav-item nav-item-1"><a href="index.html" >Python/C API Reference Manual</a> »</li>
|
||
<li class="nav-item nav-item-2"><a href="abstract.html" >Abstract Objects Layer</a> »</li>
|
||
<li class="right">
|
||
|
||
|
||
<div class="inline-search" style="display: none" role="search">
|
||
<form class="inline-search" action="../search.html" method="get">
|
||
<input placeholder="Quick search" type="text" name="q" />
|
||
<input type="submit" value="Go" />
|
||
<input type="hidden" name="check_keywords" value="yes" />
|
||
<input type="hidden" name="area" value="default" />
|
||
</form>
|
||
</div>
|
||
<script type="text/javascript">$('.inline-search').show(0);</script>
|
||
|
|
||
</li>
|
||
|
||
</ul>
|
||
</div>
|
||
<div class="footer">
|
||
© <a href="../copyright.html">Copyright</a> 2001-2019, Python Software Foundation.
|
||
<br />
|
||
The Python Software Foundation is a non-profit corporation.
|
||
<a href="https://www.python.org/psf/donations/">Please donate.</a>
|
||
<br />
|
||
Last updated on Jul 13, 2019.
|
||
<a href="../bugs.html">Found a bug</a>?
|
||
<br />
|
||
Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 2.0.1.
|
||
</div>
|
||
|
||
</body>
|
||
</html> |