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<a href="lxml-module.html">Package lxml</a> ::
Module pyclasslookup
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<!-- ==================== MODULE DESCRIPTION ==================== -->
<h1 class="epydoc">Module pyclasslookup</h1><p class="nomargin-top"></p>
<p>A whole-tree Element class lookup scheme for <a href="lxml.etree-module.html" class="link">lxml.etree</a>.</p>
<p>This class lookup scheme allows access to the entire XML tree in
read-only mode. To use it, let a class inherit from
<a href="lxml.pyclasslookup.PythonElementClassLookup-class.html" class="link">PythonElementClassLookup</a> and re-implement the <tt class="rst-docutils literal"><span class="pre">lookup(self,</span> <span class="pre">doc,</span>
<span class="pre">root)</span></tt> method:</p>
<blockquote>
<pre class="py-doctest">
<span class="py-prompt">>>> </span><span class="py-keyword">from</span> lxml <span class="py-keyword">import</span> etree, pyclasslookup
<span class="py-prompt">>>></span>
<span class="py-prompt">>>> </span><span class="py-keyword">class</span> <span class="py-defname">MyElementClass</span>(etree.ElementBase):
<span class="py-more">... </span> honkey = True
<span class="py-more">...</span>
<span class="py-prompt">>>> </span><span class="py-keyword">class</span> <span class="py-defname">MyLookup</span>(pyclasslookup.PythonElementClassLookup):
<span class="py-more">... </span> <span class="py-keyword">def</span> <span class="py-defname">lookup</span>(self, doc, root):
<span class="py-more">... </span> <span class="py-keyword">if</span> root.tag == <span class="py-string">"sometag"</span>:
<span class="py-more">... </span> return MyElementClass
<span class="py-more">... </span> <span class="py-keyword">else</span>:
<span class="py-more">... </span> <span class="py-keyword">for</span> child <span class="py-keyword">in</span> root:
<span class="py-more">... </span> <span class="py-keyword">if</span> child.tag == <span class="py-string">"someothertag"</span>:
<span class="py-more">... </span> return MyElementClass
<span class="py-more">... </span> <span class="py-comment"># delegate to default</span>
<span class="py-more">... </span> return None</pre>
</blockquote>
<p>Note that the API of the Element objects is not complete. It is
purely read-only and does not support all features of the normal
<a href="lxml.etree-module.html" class="link">lxml.etree</a> API (such as XPath, extended slicing or some iteration
methods).</p>
<p>Also, you cannot wrap such a read-only Element in an ElementTree, and
you must take care not to keep a reference to them outside of the
<code class="link">lookup()</code> method.</p>
<p>See <a class="rst-reference" href="http://codespeak.net/lxml/element_classes.html" target="_top">http://codespeak.net/lxml/element_classes.html</a></p>
<hr />
<div class="fields"> <p><strong>Version:</strong>
2.0.10-60473
</p>
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<span class="table-header">Classes</span></td>
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<a href="lxml.pyclasslookup.PythonElementClassLookup-class.html" class="summary-name">PythonElementClassLookup</a><br />
PythonElementClassLookup(self, fallback=None)
Element class lookup based on a subclass method.
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