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<H1><A NAME="SECTION005700000000000000000">
3.7 <tt class="module">UserDict</tt> --
Class wrapper for dictionary objects</A>
</H1>
<P>
<P>
<span class="note"><b class="label">Note:</b>
This module is available for backward compatibility only. If
you are writing code that does not need to work with versions of
Python earlier than Python 2.2, please consider subclassing directly
from the built-in <tt class="class">dictionary</tt> type.</span>
<P>
This module defines a class that acts as a wrapper around
dictionary objects. It is a useful base class for
your own dictionary-like classes, which can inherit from
them and override existing methods or add new ones. In this way one
can add new behaviors to dictionaries.
<P>
The <tt class="module">UserDict</tt> module defines the <tt class="class">UserDict</tt> class:
<P>
<dl><dt><b><span class="typelabel">class</span> <a name="l2h-375"><tt class="class">UserDict</tt></a></b>(<big>[</big><var>initialdata</var><big>]</big>)
<dd>
Class that simulates a dictionary. The instance's
contents are kept in a regular dictionary, which is accessible via the
<tt class="member">data</tt> attribute of <tt class="class">UserDict</tt> instances. If
<var>initialdata</var> is provided, <tt class="member">data</tt> is initialized with its
contents; note that a reference to <var>initialdata</var> will not be kept,
allowing it be used used for other purposes.
</dl>
<P>
In addition to supporting the methods and operations of mappings (see
section <A href="typesmapping.html#typesmapping">2.2.7</A>), <tt class="class">UserDict</tt> instances provide the
following attribute:
<P>
<dl><dt><b><a name="l2h-376"><tt class="member">data</tt></a></b>
<dd>
A real dictionary used to store the contents of the <tt class="class">UserDict</tt>
class.
</dl>
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<span class="release-info">Release 2.2, documentation updated on December 21, 2001.</span>
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