D7net
Home
Console
Upload
information
Create File
Create Folder
About
Tools
:
/
usr
/
share
/
doc
/
python2-docs
/
html
/
c-api
/
Filename :
dict.html
back
Copy
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Dictionary Objects — Python 2.7.16 documentation</title> <link rel="stylesheet" href="../_static/classic.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/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 2.7.16 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="Class and Instance Objects" href="class.html" /> <link rel="prev" title="List Objects" href="list.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/2/c-api/dict.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </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="class.html" title="Class and Instance Objects" accesskey="N">next</a> |</li> <li class="right" > <a href="list.html" title="List Objects" 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> <a href="../index.html">Python 2.7.16 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="concrete.html" accesskey="U">Concrete Objects Layer</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="dictionary-objects"> <span id="dictobjects"></span><h1>Dictionary Objects<a class="headerlink" href="#dictionary-objects" title="Permalink to this headline">¶</a></h1> <span class="target" id="index-0"></span><dl class="type"> <dt id="c.PyDictObject"> <code class="descname">PyDictObject</code><a class="headerlink" href="#c.PyDictObject" title="Permalink to this definition">¶</a></dt> <dd><p>This subtype of <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyObject</span></code></a> represents a Python dictionary object.</p> </dd></dl> <dl class="var"> <dt id="c.PyDict_Type"> <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a> <code class="descname">PyDict_Type</code><a class="headerlink" href="#c.PyDict_Type" title="Permalink to this definition">¶</a></dt> <dd><p id="index-1">This instance of <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyTypeObject</span></code></a> represents the Python dictionary type. This is exposed to Python programs as <code class="docutils literal notranslate"><span class="pre">dict</span></code> and <code class="docutils literal notranslate"><span class="pre">types.DictType</span></code>.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_Check"> int <code class="descname">PyDict_Check</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Check" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if <em>p</em> is a dict object or an instance of a subtype of the dict type.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.2: </span>Allowed subtypes to be accepted.</p> </div> </dd></dl> <dl class="function"> <dt id="c.PyDict_CheckExact"> int <code class="descname">PyDict_CheckExact</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_CheckExact" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if <em>p</em> is a dict object, but not an instance of a subtype of the dict type.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.4.</span></p> </div> </dd></dl> <dl class="function"> <dt id="c.PyDict_New"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyDict_New</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_New" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Return a new empty dictionary, or <em>NULL</em> on failure.</p> </dd></dl> <dl class="function"> <dt id="c.PyDictProxy_New"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyDictProxy_New</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *dict</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDictProxy_New" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Return a proxy object for a mapping which enforces read-only behavior. This is normally used to create a proxy to prevent modification of the dictionary for non-dynamic class types.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.2.</span></p> </div> </dd></dl> <dl class="function"> <dt id="c.PyDict_Clear"> void <code class="descname">PyDict_Clear</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Clear" title="Permalink to this definition">¶</a></dt> <dd><p>Empty an existing dictionary of all key-value pairs.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_Contains"> int <code class="descname">PyDict_Contains</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Contains" title="Permalink to this definition">¶</a></dt> <dd><p>Determine if dictionary <em>p</em> contains <em>key</em>. If an item in <em>p</em> is matches <em>key</em>, return <code class="docutils literal notranslate"><span class="pre">1</span></code>, otherwise return <code class="docutils literal notranslate"><span class="pre">0</span></code>. On error, return <code class="docutils literal notranslate"><span class="pre">-1</span></code>. This is equivalent to the Python expression <code class="docutils literal notranslate"><span class="pre">key</span> <span class="pre">in</span> <span class="pre">p</span></code>.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.4.</span></p> </div> </dd></dl> <dl class="function"> <dt id="c.PyDict_Copy"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyDict_Copy</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Copy" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Return a new dictionary that contains the same key-value pairs as <em>p</em>.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 1.6.</span></p> </div> </dd></dl> <dl class="function"> <dt id="c.PyDict_SetItem"> int <code class="descname">PyDict_SetItem</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *key</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *val</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_SetItem" title="Permalink to this definition">¶</a></dt> <dd><p>Insert <em>value</em> into the dictionary <em>p</em> with a key of <em>key</em>. <em>key</em> must be <a class="reference internal" href="../glossary.html#term-hashable"><span class="xref std std-term">hashable</span></a>; if it isn’t, <a class="reference internal" href="../library/exceptions.html#exceptions.TypeError" title="exceptions.TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> will be raised. Return <code class="docutils literal notranslate"><span class="pre">0</span></code> on success or <code class="docutils literal notranslate"><span class="pre">-1</span></code> on failure.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_SetItemString"> int <code class="descname">PyDict_SetItemString</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em>, const char<em> *key</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *val</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_SetItemString" title="Permalink to this definition">¶</a></dt> <dd><p id="index-2">Insert <em>value</em> into the dictionary <em>p</em> using <em>key</em> as a key. <em>key</em> should be a <code class="xref c c-type docutils literal notranslate"><span class="pre">char*</span></code>. The key object is created using <code class="docutils literal notranslate"><span class="pre">PyString_FromString(key)</span></code>. Return <code class="docutils literal notranslate"><span class="pre">0</span></code> on success or <code class="docutils literal notranslate"><span class="pre">-1</span></code> on failure.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_DelItem"> int <code class="descname">PyDict_DelItem</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_DelItem" title="Permalink to this definition">¶</a></dt> <dd><p>Remove the entry in dictionary <em>p</em> with key <em>key</em>. <em>key</em> must be hashable; if it isn’t, <a class="reference internal" href="../library/exceptions.html#exceptions.TypeError" title="exceptions.TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> is raised. Return <code class="docutils literal notranslate"><span class="pre">0</span></code> on success or <code class="docutils literal notranslate"><span class="pre">-1</span></code> on failure.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_DelItemString"> int <code class="descname">PyDict_DelItemString</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em>, char<em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_DelItemString" title="Permalink to this definition">¶</a></dt> <dd><p>Remove the entry in dictionary <em>p</em> which has a key specified by the string <em>key</em>. Return <code class="docutils literal notranslate"><span class="pre">0</span></code> on success or <code class="docutils literal notranslate"><span class="pre">-1</span></code> on failure.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_GetItem"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyDict_GetItem</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_GetItem" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: Borrowed reference.</em><p>Return the object from dictionary <em>p</em> which has a key <em>key</em>. Return <em>NULL</em> if the key <em>key</em> is not present, but <em>without</em> setting an exception.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_GetItemString"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyDict_GetItemString</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em>, const char<em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_GetItemString" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: Borrowed reference.</em><p>This is the same as <a class="reference internal" href="#c.PyDict_GetItem" title="PyDict_GetItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyDict_GetItem()</span></code></a>, but <em>key</em> is specified as a <code class="xref c c-type docutils literal notranslate"><span class="pre">char*</span></code>, rather than a <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyObject*</span></code></a>.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_Items"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyDict_Items</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Items" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Return a <a class="reference internal" href="list.html#c.PyListObject" title="PyListObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyListObject</span></code></a> containing all the items from the dictionary, as in the dictionary method <a class="reference internal" href="../library/stdtypes.html#dict.items" title="dict.items"><code class="xref py py-meth docutils literal notranslate"><span class="pre">dict.items()</span></code></a>.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_Keys"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyDict_Keys</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Keys" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Return a <a class="reference internal" href="list.html#c.PyListObject" title="PyListObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyListObject</span></code></a> containing all the keys from the dictionary, as in the dictionary method <a class="reference internal" href="../library/stdtypes.html#dict.keys" title="dict.keys"><code class="xref py py-meth docutils literal notranslate"><span class="pre">dict.keys()</span></code></a>.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_Values"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyDict_Values</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Values" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Return a <a class="reference internal" href="list.html#c.PyListObject" title="PyListObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyListObject</span></code></a> containing all the values from the dictionary <em>p</em>, as in the dictionary method <a class="reference internal" href="../library/stdtypes.html#dict.values" title="dict.values"><code class="xref py py-meth docutils literal notranslate"><span class="pre">dict.values()</span></code></a>.</p> </dd></dl> <dl class="function"> <dt id="c.PyDict_Size"> Py_ssize_t <code class="descname">PyDict_Size</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Size" title="Permalink to this definition">¶</a></dt> <dd><p id="index-3">Return the number of items in the dictionary. This is equivalent to <code class="docutils literal notranslate"><span class="pre">len(p)</span></code> on a dictionary.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.5: </span>This function returned an <code class="xref c c-type docutils literal notranslate"><span class="pre">int</span></code> type. This might require changes in your code for properly supporting 64-bit systems.</p> </div> </dd></dl> <dl class="function"> <dt id="c.PyDict_Next"> int <code class="descname">PyDict_Next</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em>, Py_ssize_t<em> *ppos</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> **pkey</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> **pvalue</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Next" title="Permalink to this definition">¶</a></dt> <dd><p>Iterate over all key-value pairs in the dictionary <em>p</em>. The <code class="xref c c-type docutils literal notranslate"><span class="pre">Py_ssize_t</span></code> referred to by <em>ppos</em> must be initialized to <code class="docutils literal notranslate"><span class="pre">0</span></code> prior to the first call to this function to start the iteration; the function returns true for each pair in the dictionary, and false once all pairs have been reported. The parameters <em>pkey</em> and <em>pvalue</em> should either point to <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyObject*</span></code></a> variables that will be filled in with each key and value, respectively, or may be <em>NULL</em>. Any references returned through them are borrowed. <em>ppos</em> should not be altered during iteration. Its value represents offsets within the internal dictionary structure, and since the structure is sparse, the offsets are not consecutive.</p> <p>For example:</p> <div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="n">PyObject</span> <span class="o">*</span><span class="n">key</span><span class="p">,</span> <span class="o">*</span><span class="n">value</span><span class="p">;</span> <span class="n">Py_ssize_t</span> <span class="n">pos</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="k">while</span> <span class="p">(</span><span class="n">PyDict_Next</span><span class="p">(</span><span class="n">self</span><span class="o">-></span><span class="n">dict</span><span class="p">,</span> <span class="o">&</span><span class="n">pos</span><span class="p">,</span> <span class="o">&</span><span class="n">key</span><span class="p">,</span> <span class="o">&</span><span class="n">value</span><span class="p">))</span> <span class="p">{</span> <span class="cm">/* do something interesting with the values... */</span> <span class="p">...</span> <span class="p">}</span> </pre></div> </div> <p>The dictionary <em>p</em> should not be mutated during iteration. It is safe (since Python 2.1) to modify the values of the keys as you iterate over the dictionary, but only so long as the set of keys does not change. For example:</p> <div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="n">PyObject</span> <span class="o">*</span><span class="n">key</span><span class="p">,</span> <span class="o">*</span><span class="n">value</span><span class="p">;</span> <span class="n">Py_ssize_t</span> <span class="n">pos</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="k">while</span> <span class="p">(</span><span class="n">PyDict_Next</span><span class="p">(</span><span class="n">self</span><span class="o">-></span><span class="n">dict</span><span class="p">,</span> <span class="o">&</span><span class="n">pos</span><span class="p">,</span> <span class="o">&</span><span class="n">key</span><span class="p">,</span> <span class="o">&</span><span class="n">value</span><span class="p">))</span> <span class="p">{</span> <span class="kt">int</span> <span class="n">i</span> <span class="o">=</span> <span class="n">PyInt_AS_LONG</span><span class="p">(</span><span class="n">value</span><span class="p">)</span> <span class="o">+</span> <span class="mi">1</span><span class="p">;</span> <span class="n">PyObject</span> <span class="o">*</span><span class="n">o</span> <span class="o">=</span> <span class="n">PyInt_FromLong</span><span class="p">(</span><span class="n">i</span><span class="p">);</span> <span class="k">if</span> <span class="p">(</span><span class="n">o</span> <span class="o">==</span> <span class="nb">NULL</span><span class="p">)</span> <span class="k">return</span> <span class="o">-</span><span class="mi">1</span><span class="p">;</span> <span class="k">if</span> <span class="p">(</span><span class="n">PyDict_SetItem</span><span class="p">(</span><span class="n">self</span><span class="o">-></span><span class="n">dict</span><span class="p">,</span> <span class="n">key</span><span class="p">,</span> <span class="n">o</span><span class="p">)</span> <span class="o"><</span> <span class="mi">0</span><span class="p">)</span> <span class="p">{</span> <span class="n">Py_DECREF</span><span class="p">(</span><span class="n">o</span><span class="p">);</span> <span class="k">return</span> <span class="o">-</span><span class="mi">1</span><span class="p">;</span> <span class="p">}</span> <span class="n">Py_DECREF</span><span class="p">(</span><span class="n">o</span><span class="p">);</span> <span class="p">}</span> </pre></div> </div> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.5: </span>This function used an <code class="xref c c-type docutils literal notranslate"><span class="pre">int</span> <span class="pre">*</span></code> type for <em>ppos</em>. This might require changes in your code for properly supporting 64-bit systems.</p> </div> </dd></dl> <dl class="function"> <dt id="c.PyDict_Merge"> int <code class="descname">PyDict_Merge</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *a</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *b</em>, int<em> override</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Merge" title="Permalink to this definition">¶</a></dt> <dd><p>Iterate over mapping object <em>b</em> adding key-value pairs to dictionary <em>a</em>. <em>b</em> may be a dictionary, or any object supporting <a class="reference internal" href="mapping.html#c.PyMapping_Keys" title="PyMapping_Keys"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyMapping_Keys()</span></code></a> and <a class="reference internal" href="object.html#c.PyObject_GetItem" title="PyObject_GetItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_GetItem()</span></code></a>. If <em>override</em> is true, existing pairs in <em>a</em> will be replaced if a matching key is found in <em>b</em>, otherwise pairs will only be added if there is not a matching key in <em>a</em>. Return <code class="docutils literal notranslate"><span class="pre">0</span></code> on success or <code class="docutils literal notranslate"><span class="pre">-1</span></code> if an exception was raised.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.2.</span></p> </div> </dd></dl> <dl class="function"> <dt id="c.PyDict_Update"> int <code class="descname">PyDict_Update</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *a</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *b</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_Update" title="Permalink to this definition">¶</a></dt> <dd><p>This is the same as <code class="docutils literal notranslate"><span class="pre">PyDict_Merge(a,</span> <span class="pre">b,</span> <span class="pre">1)</span></code> in C, and is similar to <code class="docutils literal notranslate"><span class="pre">a.update(b)</span></code> in Python except that <a class="reference internal" href="#c.PyDict_Update" title="PyDict_Update"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyDict_Update()</span></code></a> doesn’t fall back to the iterating over a sequence of key value pairs if the second argument has no “keys” attribute. Return <code class="docutils literal notranslate"><span class="pre">0</span></code> on success or <code class="docutils literal notranslate"><span class="pre">-1</span></code> if an exception was raised.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.2.</span></p> </div> </dd></dl> <dl class="function"> <dt id="c.PyDict_MergeFromSeq2"> int <code class="descname">PyDict_MergeFromSeq2</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *a</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *seq2</em>, int<em> override</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDict_MergeFromSeq2" title="Permalink to this definition">¶</a></dt> <dd><p>Update or merge into dictionary <em>a</em>, from the key-value pairs in <em>seq2</em>. <em>seq2</em> must be an iterable object producing iterable objects of length 2, viewed as key-value pairs. In case of duplicate keys, the last wins if <em>override</em> is true, else the first wins. Return <code class="docutils literal notranslate"><span class="pre">0</span></code> on success or <code class="docutils literal notranslate"><span class="pre">-1</span></code> if an exception was raised. Equivalent Python (except for the return value):</p> <div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="n">def</span> <span class="n">PyDict_MergeFromSeq2</span><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">seq2</span><span class="p">,</span> <span class="n">override</span><span class="p">)</span><span class="o">:</span> <span class="k">for</span> <span class="n">key</span><span class="p">,</span> <span class="n">value</span> <span class="n">in</span> <span class="nl">seq2</span><span class="p">:</span> <span class="k">if</span> <span class="n">override</span> <span class="n">or</span> <span class="n">key</span> <span class="n">not</span> <span class="n">in</span> <span class="nl">a</span><span class="p">:</span> <span class="n">a</span><span class="p">[</span><span class="n">key</span><span class="p">]</span> <span class="o">=</span> <span class="n">value</span> </pre></div> </div> <div class="versionadded"> <p><span class="versionmodified">New in version 2.2.</span></p> </div> </dd></dl> </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="list.html" title="previous chapter">List Objects</a></p> <h4>Next topic</h4> <p class="topless"><a href="class.html" title="next chapter">Class and Instance Objects</a></p> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../_sources/c-api/dict.rst.txt" rel="nofollow">Show Source</a></li> </ul> </div> <div id="searchbox" style="display: none" role="search"> <h3>Quick search</h3> <div class="searchformwrapper"> <form class="search" action="../search.html" method="get"> <input 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> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </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="class.html" title="Class and Instance Objects" >next</a> |</li> <li class="right" > <a href="list.html" title="List Objects" >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> <a href="../index.html">Python 2.7.16 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="concrete.html" >Concrete Objects Layer</a> »</li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 1990-2019, 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 Mar 27, 2019. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.7.6. </div> </body> </html>