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markup fiddling

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Mark Pilgrim
2009-08-14 23:16:04 -04:00
parent 6094e9dbac
commit 43310ed0a9
10 changed files with 27 additions and 27 deletions
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@@ -320,9 +320,9 @@ mark{display:inline}
<samp class=pp>{}</samp></pre>
<ol>
<li>The <code>attrib</code> property is a dictionary of the element&#8217;s attributes. The original markup here was <code>&lt;feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'></code>. The <code>xml:</code> prefix refers to a built-in namespace that every <abbr>XML</abbr> document can use without declaring it.
<li>The fifth child&nbsp;&mdash;&nbsp;<code>[4]</code> in a <code>0</code>-based list&nbsp;&mdash;&nbsp;is the <code>link</code> element.
<li>The fifth child&nbsp;&mdash;&nbsp;<code>[4]</code> in a 0-based list&nbsp;&mdash;&nbsp;is the <code>link</code> element.
<li>The <code>link</code> element has three attributes: <code>href</code>, <code>type</code>, and <code>rel</code>.
<li>The fourth child&nbsp;&mdash;&nbsp;<code>[3]</code> in a <code>0</code>-based list&nbsp;&mdash;&nbsp;is the <code>updated</code> element.
<li>The fourth child&nbsp;&mdash;&nbsp;<code>[3]</code> in a 0-based list&nbsp;&mdash;&nbsp;is the <code>updated</code> element.
<li>The <code>updated</code> element has no attributes, so its <code>.attrib</code> is just an empty dictionary.
</ol>
@@ -386,7 +386,7 @@ mark{display:inline}
</ol>
<blockquote class=note>
<p><span class=u>&#x261E;</span>There is a &#8220;gotcha&#8221; with the <code>find()</code> method that will eventually bite you. In a boolean context, ElementTree element objects will evaluate to <code>False</code> if they contain no children (<i>i.e.</i> if <code>len(element)</code> is <code>0</code>). This means that <code>if element.find('...')</code> is not testing whether the <code>find()</code> method found a matching element; it&#8217;s testing whether that matching element has any child elements! To test whether the <code>find()</code> method returned an element, use <code>if element.find('...') is not None</code>.
<p><span class=u>&#x261E;</span>There is a &#8220;gotcha&#8221; with the <code>find()</code> method that will eventually bite you. In a boolean context, ElementTree element objects will evaluate to <code>False</code> if they contain no children (<i>i.e.</i> if <code>len(element)</code> is 0). This means that <code>if element.find('...')</code> is not testing whether the <code>find()</code> method found a matching element; it&#8217;s testing whether that matching element has any child elements! To test whether the <code>find()</code> method returned an element, use <code>if element.find('...') is not None</code>.
</blockquote>
<p>There <em>is</em> a way to search for <em>descendant</em> elements, <i>i.e.</i> children, grandchildren, and any element at any nesting level.